What is this insect I found in northern Europe?

What is this insect I found in northern Europe?

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Found this one in my bed in Northern Europe.

Around 6 mm long (5 mm body + 1 mm nozzle). Seems to have 6 legs. The back looks a bit like black-brown camouflage, the legs are red-brown, the nozzle is black.

Could this be some kind of bed bug?

Definitely not a bedbug. It is a weevil, family Curculionidae. A beetle, and not normally found indoors. It looks a bit like Baris, but I cannot tell from the picture.

Insect evolution: Insect evolution

Scientists at Ludwig-Maximilians-Universitaet (LMU) in Munich have shown that the incidence of midge and fly larvae in amber is far higher than previously thought. The new finds shed light on insect evolution and the ecology in the Baltic amber forest during the Eocene epoch.

In the Eocene epoch - between 56 and 33.9 million years ago - much of Northern Europe was covered by a huge forest, now referred to as the Baltic amber forest. The forest was probably dominated by pines and oaks, but also comprised representatives of many other deciduous species and conifers, including tropical taxa. The resins produced by the forest account for all of Europe's amber, including the samples in which the LMU zoologists Viktor Baranov, Mario Schädel and Joachim T. Haug have now discovered many examples of entrapped midge and fly larvae. In a paper published in the online journal PeerJ, they point out that these finds refute the widespread notion that amber is devoid of such fossils. Their analysis also provides new evidence in relation to the ecology of the amber forests of Eocene age, which supports a new interpretation of this habitat as a warm to temperate seasonal humid forest ecosystem. Flies and midges (Diptera) make up one of the most diverse groups of insects found in Germany. Their larval forms are an important element of many ecosystems and play a significant role in, for example, the decomposition and recycling of biomass. In spite of their ecological prominence, little is known about the evolution of dipteran larvae, and the fossilized specimens that have so far come to light - in particular those characteristic of terrestrial ecosystems - have so far been little studied. The authors of the new study have now identified more than 100 larvae in amber inclusions assembled by collectors in Northern Germany. The samples described come from either the Baltic or the Bitterfeld section of the amber forest. Most of the dipterans identified, belong to the group known as

Bibionomorpha, whose evolutionary history extends over a period of more than 200 million years. With a total of 35 specimens, the group most frequently represented is the genus Mycetobia, which belongs to the Family Anisopodidae (whose members are commonly known as window gnats). Thanks to the abundance of this material, the researchers were able to reconstruct the relative growth rate of these larvae based on the length and width of the head capsule. The results confirmed that these gnats went through four larval stages, just like the present-day representatives of the same group. In addition, their overall morphology is very similar to that of extant window gnats. "Since the morphologies of the other fossil bibionomorphan larvae are also very reminiscent of their recent relatives, we can safely assume that they occupied habitats similar to those of our contemporary forms," says Baranov, first author of the new paper. The presence of large numbers of Mycetobia larvae among the specimens examined therefore implies that Europe's amber forests were characterized by moist conditions and an abundance of decaying organic matter. Moreover, the researchers also discovered the first fossilized larva that could be assigned to the Pachyneura (Diptera, Pachyneuridae), and recent are associated with dead wood in undisturbed woodland. "Within the scientific community, a new interpretation of Europe's amber forests is currently emerging. This is based on paleobotanical and isotope evidence which suggests that these woods constituted a warm-to-temperate seasonal ecosystem. Our findings provide further support for this picture," Baranov explains. He and his colleagues argue that it is quite conceivable that, under the climatic conditions prevailing in Europe during the Eocene, a subtropical, seasonal forest would have supplied abundant amounts of decaying organic matter in the form of leaf litter and dead plants and animals, as well as bacterial biofilms and fungi. In any case, the dipteran larvae provide an independent source of information that can be used to reconstruct the nature of the paleohabitats. "Perhaps our most surprising find is a larva which we identified as a representative of a previously unknown group," says Baranov. While this larva belongs among the march flies (Diptera, Bibionidae), it exhibits a very unusual combination of morphological characters which finds no parallel among modern representatives of this group." In Baranov's opinion, the specimen may document an experimental phase of their evolution, during which different lineages independently "discovered" similar sets of morphological traits.

Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.

World seeing 'catastrophic collapse' of insects: study

Charts showing declining and threatened insects and vertebrates, according to IUCN data

Nearly half of all insect species worldwide are in rapid decline and a third could disappear altogether, according to a study warning of dire consequences for crop pollination and natural food chains.

"Unless we change our way of producing food, insects as a whole will go down the path of extinction in a few decades," concluded the peer-reviewed study, which is set for publication in April.

The recent decline in bugs that fly, crawl, burrow and skitter across still water is part of a gathering "mass extinction," only the sixth in the last half-billion years.

"We are witnessing the largest extinction event on Earth since the late Permian and Cretaceous periods," the authors noted.

The Permian end-game 252 million years ago snuffed out more than 90 percent of the planet's life forms, while the abrupt finale of the Cretaceous 66 million years ago saw the demise of land dinosaurs.

"We estimate the current proportion of insect species in decline—41 percent—to be twice as high as that of vertebrates," or animals with a backbone, Francisco Sanchez-Bayo of the University of Sydney and Kris Wyckhuys of the University of Queensland in Australia reported.

"At present, a third of all insect species are threatened with extinction."

One-in-six species of bees have gone regionally extinct somewhere in the world

An additional one percent join their ranks every year, they estimated. Insect biomass—sheer collective weight—is declining annually by about 2.5 percent worldwide.

"Only decisive action can avert a catastrophic collapse of nature's ecosystems," the authors cautioned.

Restoring wilderness areas and a drastic reduction in the use of pesticides and chemical fertiliser are likely the best way to slow the insect loss, they said.

'Hardly any insects left'

The study, to be published in the journal Biological Conservation, pulled together data from more than 70 datasets from across the globe, some dating back more than a century.

By a large margin, habitat change—deforestation, urbanisation, conversion to farmland—emerged as the biggest cause of insect decline and extinction threat.

Pollution is one of the main reasons for the decline in insect populations

Next was pollution and the widespread use of pesticides in commercial agriculture.

The recent collapse, for example, of many bird species in France was traced to the use insecticides on industrial crops such as wheat, barley, corn and wine grapes.

"There are hardly any insects left—that's the number one problem," said Vincent Bretagnolle, an ecologist at Centre for Biological Studies.

Experts estimate that flying insects across Europe have declined 80 percent on average, causing bird populations to drop by more than 400 million in three decades.

Only a few species of insects—mainly in the tropics—are thought to have suffered due to climate change, while some in northern climes have expanded their range as temperatures warm.

In the long run, however, scientists fear that global warming could become another major driver of insect demise.

Experts estimate that flying insects across Europe have declined 80 percent on average

Up to now, rising concern about biodiversity loss has mostly focused on big mammals, birds and amphibians.

But insects comprise about two-thirds of all terrestrial species, and have been the foundation of key ecosystems since emerging almost 400 million years ago.

"The essential role that insects play as food items of many vertebrates is often forgotten," the researchers said.

Moles, hedgehogs, anteaters, lizards, amphibians, most bats, many birds and fish all feed on insects or depend on them for rearing their offspring.

Other insects filling the void left by declining species probably cannot compensate for the sharp drop in biomass, the study said.

Habitat change—deforestation, urbanisation, conversion to farmland—emerged as the biggest cause of insect decline and extinction threat

Insects are also the world's top pollinators—75 percent of 115 top global food crops depend on animal pollination, including cocoa, coffee, almonds and cherries.

One-in-six species of bees have gone regionally extinct somewhere in the world.

Dung beetles in the Mediterranean basin have also been hit particularly hard, with more than 60 percent of species fading in numbers.

The pace of insect decline appears to be the same in tropical and temperate climates, though there is far more data from North America and Europe than the rest of the world.

Britain has seen a measurable decline across 60 percent of its large insect groups, or taxa, followed by North America (51 percent) and Europe as a whole (44 percent).

Environmental drivers of voltinism and body size in insect assemblages across Europe

Correspondence: Dirk Zeuss, Faculty of Biology, Department of Ecology – Animal Ecology, Philipps-Universität Marburg, Karl-von-Frisch-Strasse 8, Marburg 35043, Germany.

Faculty of Landscape Architecture, Horticulture and Forestry, Department of Biodiversity and Species Conservation, University of Applied Science Erfurt, Erfurt, 99085 Germany

Faculty of Biology, Department of Ecology – Animal Ecology, Philipps-Universität Marburg, Marburg, 35043 Germany

Faculty of Biology, Department of Ecology – Animal Ecology, Philipps-Universität Marburg, Marburg, 35043 Germany

Correspondence: Dirk Zeuss, Faculty of Biology, Department of Ecology – Animal Ecology, Philipps-Universität Marburg, Karl-von-Frisch-Strasse 8, Marburg 35043, Germany.

Faculty of Landscape Architecture, Horticulture and Forestry, Department of Biodiversity and Species Conservation, University of Applied Science Erfurt, Erfurt, 99085 Germany

Faculty of Biology, Department of Ecology – Animal Ecology, Philipps-Universität Marburg, Marburg, 35043 Germany


General geographical patterns of insect body size are still a matter of considerable debate, mainly because the annual number of generations (voltinism) and its relationship with body size have largely been ignored. We present the first analyses of voltinism and body size of insect assemblages at a continental scale using lepidopteran and odonate species. We hypothesize that voltinism is strongly driven by environmental conditions and constrains body size on macroecological scales.



We compiled the distribution, voltinism and body size of 943 lepidopteran and odonate species within a 50 km × 50 km grid system, thereby presenting a novel method for estimating the body volume of species from digital images. Regressions and structural equation modelling were applied to distinguish the effects of temperature, productivity and season length on mean voltinism and body size within grid cells. We accounted for spatial autocorrelation with autoregressive models and analysed the possible effect of species richness and intraspecific variability.


Voltinism consistently decreased with latitude for both lepidopterans (r 2 = 0.76) and odonates (r 2 = 0.86), with species having on average fewer generations per year in northern Europe and more generations per year in southern Europe. The effects of temperature, productivity and season length on body size contrasted in sign between lepidopterans and odonates, leading to opposing geographical patterns across Europe.

Main conclusions

Voltinism in insect assemblages is strongly driven by environmental temperature, and trade-offs between voltinism and body size influence the occurrence of species at macroecological scales. Insects with the ability to extend their generation time over multiple years can overcome this constraint, allowing for a relatively large body size in cold areas. Our results furthermore support the idea that body sizes of terrestrial and aquatic insects form contrasting geographical patterns because they are differently affected by temperature and resource constraints.

Double trouble: Invasive insect species overlooked as a result of a shared name

An invasive leaf-mining moth, feeding on cornelian cherry, has been gradually expanding its distributional range from its native Central Europe northwards for a period likely longer than 60 years. During that period, it has remained under the cover of a taxonomic confusion, while going by a name shared with another species that feeds on common dogwood.

To reproduce, this group of leaf-mining moths lay their eggs in specific plants, where the larvae make tunnels or 'mines', in the leaves. At the end of these burrows, they bite off an oval section, in which they can later pupate. These cutouts are also termed 'shields', prompting the common name of the family, the shield-bearer moths.

During a routine study into the DNA of leaf-mining moths, Erik van Nieukerken, researcher at Naturalis Biodiversity Center, Leiden, the Netherlands, discovered that the DNA barcodes of the species feeding on common dogwood and cornelian cherry were in fact so different that they could only arise from two separate species. As a result, Erik teamed up with several other scientists and amateur entomologists to initiate a more in-depth taxonomic study.

Curiously, it turned out that the two species had been first identified on their own as early as in 1899, before being described in detail by a Polish scientist in the 50s. Ironically, it was another Polish study, published in the 70s, that regarded the evidence listed in that description as insufficient and synonymised the two leaf-miners under a common name (Antispila treitschkiella).

Now, as a result of the recent study undertaken by van Nieukerken and his collaborators, the two moth species -- Antispila treitschkiella and Antispila petryi -- have their diagnostic features listed in a research article published in the open access journal Nota Lepidopterologica.

"We now establish that the species feeding on common dogwood, A. petryi, does not differ only in its DNA barcode, but also in characters of the larva, genitalia and life history," explains Erik van Nieukerken. "A. petryi has a single annual generation, with larvae found from August to November, whereas A. treitschkiella, which feeds on cornelian cherry, has two generations, with larvae occurring in June-July and once again between September and November."

While van Nieukerken and his team were working on the taxonomy of the moths, David C. Lees of the Natural History Museum, London, spotted a female leaf-miner in the Wildlife Garden of the museum. Following consultation with van Nieukerken, it turned out that the specimen in question was the first genuine A. treitschkiella ever to be found in Britain. Subsequently, the research groups decided to join forces, leading to the present discovery.

Despite the lack of data for the British Isles, it is already known that, in continental Europe, the cornelian cherry-feeding species had established in the Netherlands and much of Germany in the 1990s.

With common dogwood being widely planted, it is now suspected that A. petryi has recently reached Sweden and Estonia, even though there was no previous evidence of the leaf-miner expanding its range.

"This discovery should provoke the attention of gardeners and other members of the public alike to the invasive leafminers attacking some of our much admired trees and shrubs, as we have demonstrated for the cornelian cherry -- a species well-known for its showy red berries in the autumn," says David Lees.

"Especially in Britain, we hope that they check their photos for the conspicuous leaf mines, recognisable by those oval cutouts, to see if they can solve the mystery of when the invasion, which is now prominent on cornels around London, actually started, and how fast it progresses. Citizen scientists can help."

General features

Termites, which number about 2,750 species, are distributed widely, reaching their greatest abundance in numbers and species in tropical rainforests around the world (see video ). In North America termites are found as far north as Vancouver, British Columbia (Zootermopsis), on the Pacific coast, and Maine and eastern Canada (Reticulitermes) on the Atlantic coast. In Europe the northern limit of natural distribution is reached by Reticulitermes lucifugus on the Atlantic coast of France, although an introduced species, Reticulitermes flavipes, occurs as far north as Hamburg, Germany. The known European species of termites have a predominantly Mediterranean distribution and do not occur naturally in Great Britain, Scandinavia, Switzerland, Germany, or northern Russia. In the Far East Reticulitermes speratus ranges as far north as South Korea, Peking, and northern Japan. Termites occur also in the Cape region of South Africa, Australia, Tasmania, and New Zealand.

In addition to naturally occurring termites, many species have been inadvertently transported by humans from their native habitats to new parts of the world. Termites, particularly Cryptotermes and Coptotermes, have been accidentally transported in wooden articles such as shipping crates, boat timbers, lumber, and furniture. Because dry-wood termites (e.g., Cryptotermes species) live in small colonies in wood and tolerate long periods of dryness, they can survive in seasoned wood and furniture and can easily be transported over long distances. Members of the family Rhinotermitidae (e.g., Coptotermes) require access to moisture and cannot survive prolonged dry periods. Coptotermes formosanus, widely distributed in Japan, Taiwan, and South China, has been introduced into Sri Lanka (Ceylon), the Pacific islands, South Africa, East Africa, Hawaii, California, and the southern United States. C. formosanus is unusual for the family in that it can survive without direct soil contact as long as a moisture source is present. In the United States the species has been found to have well-established colonies in the upper reaches of buildings, using small leaks in the roof as a moisture source. A termite native to the United States, Reticulitermes flavipes, was found in the hothouses of the Royal Palace in Schönbrunn, in Vienna, and the species was reported and described in that location before it was discovered in the United States. The termites presumably had been shipped from North America in wooden containers of decorative potted plants.

Radar spots trillions of unseen insects migrating above us

Birds and human vacationers aren't the only creatures that take to the skies each year to migrate north or south. An analysis of a decade's worth of data from radars specifically designed to track airborne insects has revealed unseen hordes crossing parts of the southern United Kingdom—2 trillion to 5 trillion insects each year, amounting to several thousand tons of biomass, that may travel up to hundreds of kilometers a day.

The numbers, reported in this week's issue of Science , are "stunning," says Silke Bauer, an ecologist at the Swiss Ornithological Institute in Sempach. "Wow," adds Larry Stevens, an evolutionary ecologist at the Museum of Northern Arizona in Flagstaff. "Can you image what these numbers look like in tropical settings, say, over the basins of the Amazon or the Congo?"

Although some insect migrations are well known (think monarchs), the new work takes a systematic approach to flying insects and hints that such mass movements are surprisingly common. These airborne invertebrates, their bodies packed full of nitrogen and phosphorus, could move significant amounts of key nutrients across the globe. "Insects are little creatures, but collectively they can have a big impact comparable in magnitude to large ocean migrations [of plankton]," says Lael Parrott, an environmental geographer at the University of British Columbia in Kelowna, Canada.

In the 1970s, U.K. entomologists began to use mobile radars to assess movements of locusts and other pests in developing countries. By the late 1990s, they had designed a permanent upward-facing radar system, based at Rothamsted Research in Harpenden, U.K., that automatically logs insects of different sizes. In one early discovery, Jason Chapman, now at the University of Exeter in the United Kingdom, and colleagues found that certain large butterflies and moths that dwell in northern Europe in the summer and in the Mediterranean in the winter take advantage of favorable winds to migrate

Annual migrations of flying insects

Estimated biomass of migrating insects over southern United Kingdom recorded by radar and balloon flights.

Now, Gao Hu, from Nanjing Agricultural University in China, Chapman, and colleagues have surveyed data from 2000 to 2009 collected in Harpenden and two other U.K. radar sites. The radars recorded medium-sized insects (hoverflies, ladybird beetles, and water boatmen) and large ones (hawk moths, painted lady butterflies, and aquatic beetles) flying between 150 meters and 1200 meters high balloon sampling flights helped provide estimated counts for smaller insects.

Directional seasonal migrations of flying insects

The flow of insects north or south with the seasons may move a lot of nutrients across the United Kingdom.

Among the medium and large insects, the radar documented 1320 mass migrations in the daytime and 898 at night over the course of the decade. These streams of insects, heading south in the fall and north in the spring, usually coincided with favorable winds, which swept them along at up to 58 kilometers an hour. That insects "have an idea of where they want to go to, when they want to go, and what winds are good [is] surprising for these tiny creatures," Bauer says.

It will take more data, from other sites, to convince some entomologists that many insects migrate seasonally like birds and mammals. A European initiative is tracking birds using weather radars, and its scientists hope to get the funding to monitor insects as well. Such studies could be critical, notes zoologist Eric Warrant of Lund University in Sweden. "If, due to human influence, a large fraction of the [insect] migrant population is wiped out, it might have catastrophic consequences for those particular ecosystems."

Elizabeth Pennisi

Liz is a senior correspondent covering many aspects of biology for Science.

Invasive false brome grass is spreading, but Oregon's insects are biting

EUGENE, Ore. — (Nov. 15, 2011) — After hiking in Oregon, a University of Oregon plant biologist suggests, people may want to brush off their shoes and comb through their dogs in an effort to curb the spread of an invasive grass that is expanding its range.

The grass is false brome (Brachypodium sylvaticum), a native of Europe and Asia, which likely landed in Oregon by way of USDA experimental plots in 1939 near Corvallis and Eugene. This grass likely was brought in, along with other grasses from around the world, to test as a range-improvement crop, but in the test plots the genotypes crossed to create "a little monster" hybrid, according to research published in 2008 by Mitchell Cruzan of Portland State University. The grass escaped and is found today across Oregon, north to south from Astoria to Grants Pass and from west to east from the coast to near Madras, but mostly it is concentrated in the Willamette Valley.

Bitty A. Roy, a scientist in the UO's Institute of Ecology and Evolution, studies the ecology of false brome. In two new studies, Roy and colleagues report that the grass is somewhat controlled in its native Europe by two pathogenic fungi (Claviceps purpurea and Epichoë sylvatica), which block reproduction, but its only known and less-lethal enemies in Oregon are insects.

► AUDIO: Bitty Roy provides an overview of the study

The National Science Foundation-funded research is detailed in separate papers in the journals Ecology and Mycologia. The findings, Roy said, provide support for the "enemy release hypothesis," which says invading plants are free from the enemies of their native habitats. But, she added, they still fall prey to local generalists such as herbivores in the areas they invade.

Co-author Aud H. Halbritter with false brome in a natural habitat in Switzerland

Roy and colleagues studied 10 sites in Oregon and 10 in Switzerland to determine what damages are inflicted on the grass by fungi, insects, mollusk and deer. In Switzerland, they found more kinds of enemies, but the biggest ones were generalist mollusks and the two specialist fungi.

In Oregon, only generalist insects are the enemy. "Generalists can cause a lot of damage, too," Roy said. "We found that this grass actually gets eaten more by insects in its invaded range than it does in its home range."

While such insect damage may slow its growth, false brome now appears to be entrenched among the more than 25 percent of non-native plants now growing across the state, Roy said.

"There has been extraordinary, exponential growth, especially since 1989. The conditions are now perfect to spread, because it has had time to genetically evolve and adapt. We carry things around with us — sometimes accidentally, sometimes on purpose. Then they become our nemeses. This really is a case of 'this is the house that Jack built,'" Roy said, referring to a British nursery rhyme. "Once something gets here, it's really difficult to control it."

False brome also has been confirmed in both Washington state and northern California, the spread of which is monitored by the states' agricultural departments. It has also recently shown up on the East coast. "Grasses are particularly dangerous invaders. They tend to do wholesale ecosystem change," Roy said. Brachypodium sylvaticum grows really well in the shade and in the forests."

Where it grows, it blocks forests' floors, keeping tree seeds from falling to the ground and germinating. It stays green throughout even dry summers. Its impact in encouraging or retarding the spread of wildfires is currently being pursued in controlled burn studies underway by one of Roy's students in a project with the U.S. Forest Service.

There is no easy answer on how to stop the spread, Roy said. Biological control, in which another non-native species is introduced to kill an invasive plan, can backfire, she said, recalling when Oregon agricultural officials imported moths to attack tansy ragwort in the 1970s. Because the ragwort was related to native ragwort, the moths did not discriminate in their attacks and are still found in Oregon today.

For now, she said, being diligent about wiping off clothing and animals after hiking in areas where the grass grows is helpful for reducing spread. She also suggests public participation in special cleanup projects, one of which at Mt. Pisgah, southeast of Eugene, has resulted in a reduction of the grass.

Co-authors with Roy on the Ecology paper were Tobias Policha, Julie L. Stewart and G. Kai Blaisdell, all of the UO's Institute for Ecology and Evolution (IEE), Tim Coulson of Imperial College London, Wilma Blaser of both the IEE and the Institute of Integrative Biology in Switzerland, and Sabine Güsewell, also of the Swiss institute.

Co-authors with Roy on the Mycologia paper were Aud H. Halbritter and Sabine Güsewell, both of the Institute of Integrative Biology in Switzerland, and George C. Carroll of the UO Institute for Ecology and Evolution.

Wormhole Record: Centuries-Old European Woodblock Prints Show Distribution Of Wood-Boring Beetle

Wormholes aren’t just for time travel or teleportation anymore. Some very real and ancient wormholes are now helping to trace the distribution of insect species and artwork.

A biologist found himself in the unlikely world of centuries-old European woodblock print art. There, he discovered that many of the small imperfections in the prints could be identified and traced back to specific species of bugs that had burrowed through the surface of the original woodblock before the print was made. By matching the hole dimensions to the time and locations in which these prints were made, the scientist, Blair Hedges, a professor of biology at The Pennsylvania State University, has been able to paint a historic record of wood-boring beetle distribution across Europe—patterns that had been previously unknown.

Hedges has nicknamed these telltale traces the “wormhole record,” faint trails of these centuries-old animals—all told in hundreds of elegant prints.

Diagram showing beetle larva and exiting adult courtesy of Blair Hedges

Adult beetles lay eggs in the crannies of a piece of wood. Once the larvae hatch, they slowly descend into the wood, spending three or four years living there and feasting on the wood’s cellulose. After these wormlike larvae transform into adult beetles—through a pupal stage—they then burrow out of the wood, creating the noticeable holes that have so textured so many woodblock prints. These holes can also be found in furniture, oak floors and rafters, in addition to the woodblocks. Art historians have used the signs of wormholes in prints and books to place these products in order (if more traces of wormholes appear in one print of the same image than in another, the excess suggests that the original block was infested with the beetles after the print showing fewer holes was made and thus that that the version with more holes is). But they had otherwise considered the holes to be little more than blemishes in the print medium.

For a biological purpose, however, “these tiny errors or interruptions in the print serve as ‘trace fossils,’” Hedges said in a prepared statement. “They aren’t the animals themselves, but they are evidence of the animal’s existence. They show that beetles invaded a particular piece of wood, even if that wood no longer exists.”

The prints actually offer a more precise record of these invasions than the pieces of wood themselves. A beetle can lay eggs on a piece of wood at any point in time, whereas the marks from the woodblock on the paper print offer an indelible clue that the wood was infected before a particular print was made. “Because most prints, including those in books, have publication dates, we know that the wormholes in question were made very close to that date,” Hedges said. “It’s an almost perfect biological timestamp. And in most cases, we also know where the book was printed. So wormholes can tell us when and where a species existed with fairly good accuracy, more than 500 years ago, and that is amazing.”

Detail of a print marked by evidence of wormholes courtesy of Rijksmuseum, Amsterdam

Hedges studied 3,263 wormholes visible in 473 different prints made between 1462 and 1899. He found that there were two distinct sizes of holes: some were 2.3 millimeters across and others were closer to 1.4 millimeters wide. And there was a distinct pattern of these hole sizes across the European continent all of the smaller holes were found on prints made in the northeast, and the larger holes came from the southwest.

He was then able to deduce the species of each beetle. “The size of the beetle closely matches the size of the hold made, and most species have preferences for the wood they eat,” Hedges said. “This left two species as the probable hole-makers”: the common furniture beetle (Anobium punctatum) in the northeast and the Mediterranean furniture beetle (Oligomerus ptilinoides) in the southwest. Other types of wood-boring insects don’t share the same preference for dry, smooth-grained woods (such as apple, pear and box) that were used for woodblocks—instead targeting rotting, damp woods or those that are either extremely soft or extremely hard.

The line between these two beetles seemed to be surprisingly steady throughout the study period. “This is surprising because it means that the two species’ ranges were in close contact but, oddly, did not overlap along a precise dividing line,” Hedges said. Local competition and climate differences might have kept these two species apart for centuries, if not millennia.

Map of historic beetle species distribution courtesy of Blair Hedges

The discovery of historical separation is new. “Today and for the past 100 years, because travel, shipping and furniture transport tends to spread insects around, we find both species all over northern and southern Europe and elsewhere in the world,” Hedges said. Indoor controlled climates might have also helped the beetles colonize new ranges.

Hedge’s print-based method could help examine woodborer species distribution and historical ranges throughout the world, indicating changes in local populations and arrival times of invasive species. Traces of worm DNA might also still linger in some of the historic woodblocks, making it possible to support the wormhole species analyses.

The wormhole technique might also help solve some questions in art history as well. “There are some situations in which a book or print’s origin is unknown,” Hedges said. “Now that we know that different species of beetles existed in different locations in Europe, art historians can determine whether a book was from northern or southern Europe simply by measuring the wormholes.”

The findings were described online November 20 in Biology Letters.

Flower Thrips

Flower thrips (Figure 165), Frankliniella tritici (Fitch), Thripidae, THYSANOPTERA
Florida flower thrips (common name not approved by ESA), Frankliniella bispinosa Morgan, Thripidae, THYSANOPTERA


The flower thrips and the Florida flower thrips are exceedingly similar. They can be separated only by microscopic examination. Both are approximately 1 mm to 1.25 mm long and yellow, with brown blotching, especially about the middle of the thorax and abdomen (Figure H). Males are smaller than females and are lighter in color.

The flower thrips delicate egg is cylindrical, and slightly kidney-shaped, with a smooth pale or yellow surface.

The immature thrips is lemon yellow, resembling the adult except for its lack of wings.


The Florida flower thrips has been found in Florida, Georgia, and Alabama and is likely distributed in other states of the southern United States. Evidently because of their small size, flower thrips are carried over large areas by frontal wind systems, the maximum rate of migration taking place in early week of June. Trapping records by sticky cards showed that these thrips are found in relatively equal numbers up to 135 feet (45 m). They have even been trapped at altitudes of 10,000 feet (3,100 m). The flower thrips has also been reported in Western states. These thrips enter greenhouses through vents or doors, on plants brought into the house, or on people or supplies coming into the house.

Host Plants

Florida flower thrips have been reported from over one hundred species of plants. Roses and citrus are favorite hosts, particularly the white varieties. Most plants of the Rosaceae are infested. Flowers of a more or less open structure, where the stamens and pistils are easily accessible, are favorites. Flowers such as nightshade with stamens in a tube about the pistil are also favorites. Flower thrips have been collected from 29 plant orders including various berries, cotton, chrysanthemums, daisies, day lilies, field crops, forage crops, grass flowers, legumes, peonies, privet, roses, trees, truck crops, vines, and weeds. They seem to prefer grasses and yellow or light-colored blossoms. Roses are most susceptible in June.

Florida flower thrips always feeds on the most tender part of the plant, such as buds, flowers, or leaves. The effect of their numerous but shallow punctures is to give the injured tissue a shrunken appearance, and the damage is described as piercing and sucking fluids from the cells. The thrips feed on the thick fleshy petals, pistils, and stamens of the flower, and then the affected parts turn brownish-yellow, blacken, shrivel up, and drop prematurely. Infested rose blossoms turn brown, and buds open only partially. The petals, distorted with brown edges, seem to stick together. Only the epidermis and relatively few mesophyll cells are affected. They also may feed on ovary or young fruit on some host plants. The numerous and shallow punctures on the surface cause characteristic markings that lower marketability dramatically.

Life History

No published work has been done on the biology of the Florida flower thrips. The flower thrips was described in 1855 from Wisconsin. During warm periods, swarms of these tiny insects often fly in the afternoon. Flower thrips bite people, causing a noticeable stinging sensation. Their large numbers account for considerable and rapid damage to flowers, especially those with light-colored petals. Yet thrips contribute to pollination of some crops, an unexpected benefit! Flower thrips are generally found at the bases of the petals. They reproduce throughout the year in the warmer parts of the Southeast, with the majority of their 12 to 15 generations occurring in the warmer months. Newly emerged females begin to lay eggs within 1 to 4 days in summer and within 10 to 35 days in winter, reproduction being much faster in warmer weather. In summer, the adult stage is reached in about 11 days. Flower thrips pass through egg, two larval, prepupal, pupal, and adult stages. The eggs are inserted into flower or leaf tissue, and the prepupal and pupal stages are spent in the soil. In summer, flower thrips may live 26 days, though overwintering thrips may live all winter. Flower thrips can overwinter as far north as North Dakota in grass clumps and other sheltered refuges.

Insecticides are currently used by most flower growers for control of flower thrips. As these thrips are not present until the blossoms open, pesticide applications may cause flower burn. For specific insecticides and rates, consult the current Cooperative Extension publications on ornamental plant pests.

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