Insects Arthropods Arachnids

Researchers found pesticide-contaminated plants in nurseries

Milkweed plants purchased at retail nurseries across the United States were contaminated with pesticides harmful to monarch caterpillars that rely on milkweed, a study led by researchers at the University of Nevada, Reno found. Every plant sampled was contaminated, even those that were labeled friendly to wildlife.

Researchers gathered 235 milkweed leaf samples from retail nurseries across 15 states and tested them for pesticides. A total of 61 different pesticides were found, with an average of 12 per plant and as many as 28 per plant, according to the study in collaboration with the Xerces Society for Invertebrate Conservation and published Monday in the peer-reviewed science journal Biological Conservation.

Milkweed in nurseries are often purchased and planted by people hoping to support the monarch butterfly, which was recently listed on the IUCN Red List of Threatened Species™ as endangered. Western monarch caterpillars depend on milkweed for food. They are specifically adapted to the plant, which is toxic to other animals, and don’t have alternative sources of food.

“In a previous study in California that primarily looked at milkweed in agriculture and urban interfaces, we had looked at a small number of plants from retail nurseries, and found that they contained pesticides,” Matt Forister, a biology professor at the University who studies insect ecology and is a coauthor of the paper, said. “So we were prepared for this much larger sample of nursery plants to again uncover contamination, but it was surprising to see the great diversity of pesticides found in these plants. In many ways, they are as contaminated or even worse than plants growing on the edges of agricultural fields. That was a surprise, at least to me.”

While researchers couldn’t fully assess the toxic load carried by these plants, 38% of the samples had residue levels that could

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Multiple interactions in its cultivation — ScienceDaily

It’s not possible to grow cacao without insects — that’s logical. After all, they ensure that the flowers are pollinated and that the valuable cacao fruits, a sought-after material for the food industry, develop. Studies in Indonesia had shown in the past that birds and bats also contribute to increasing crop yields. However, a new study published in the journal Proceedings of the Royal Society B shows now how large this contribution is.

The study is the result of new findings from scientists from the universities of Würzburg, Göttingen and Vienna and the Alliance of Bioversity International and CIAT. The biologists responsible for the study are Justine Vansynghel, researcher at the Department of Animal Ecology and Tropical Biology at the Julius-Maximilians-Universität Würzburg (JMU), and Carolina Ocampo-Ariza, researcher at the Agroecology Department at the University of Göttingen.

Sometimes pest, sometimes pest controller

“Animals such as birds, bats and insects, but also rodents, are important for cacao agroforestry,” Justine Vansynghel explains. On the one hand, they can increase yields, for example by pollinating the plants or acting as “biological pest control agents.” On the other hand, they can reduce yields, for example when squirrels steal the valuable seeds and prefer to eat them themselves.

It was known that various animal species affect cacao cultivation and crop yield. “Until now, however, it was not clear how the individual contributions of all these animals interact and how other factors, such as the proximity of the cultivated area to a forest or its level of shading, can influence these contributions,” Carolina Ocampo-Ariza says. As part of their study, which has now been published, the two researchers therefore quantified the animals’ combined contributions to crop yield and explored how distance to the forest and shading affect productivity.

The key findings of their study are:

  • The level
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Tropical insects are extremely sensitive to changing

Insects that are adapted to perennially wet environments, like tropical rainforests, don’t tend to do well when their surroundings dry out. New research published this Wednesday indicates they may be equally averse to heavy rainfall.

The results of an extensive five-year study conducted in Peru revealed a 50% decline in arthropod biomass following short periods of both drought and increased precipitation. One of only a few studies of this scope conducted in the tropics, the findings suggest terrestrial arthropods, a group that includes insects and spiders, will be more susceptible to climate change than previously suspected.

“Most of the time when we think about climate change, we think about warming temperatures, but rainfall patterns will change as well, which is something insects seem to be especially sensitive to,” said Felicity Newell, a postdoctoral associate and former doctoral student with the Florida Museum of Natural History. “We’re seeing that rainfall extremes can have negative effects over very short timescales.”

The insect apocalypse takes on new dimensions

The discovery of a Goldilocks preference for just the right amount of water makes its debut against a worrying backdrop of population declines. Over the last two decades, thousands of studies have documented insect decline and extinction on every continent except Antarctica, a pattern some have dubbed the insect apocalypse.

These results paint a stark but incomplete picture. Most of these studies have been conducted in densely populated temperate regions, while the planet’s most biodiverse ecosystems — the tropics — have received considerably less scrutiny.

Half of all insect diversity resides in the tropics, and as a result, scientists know a great deal about only a small fraction of imperiled insect species. This imbalance places strict limits on understanding how insects will fare with the complex problem of climate change.

“One of the biggest challenges

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Soybean virus may give plant-munching bugs a boost in

Most viral infections negatively affect an organism’s health, but one plant virus in particular — soybean vein necrosis orthotospovirus, often referred to as SVNV — may actually benefit a type of insect that commonly feeds on soybean plants and can transmit the virus to the plant, causing disease, according to Penn State research.

In a laboratory study, the Penn State College of Agricultural Sciences researchers found that when soybean thrips — small insects ranging from 0.03 to 0.20 inches long — were infected with SVNV, they tended to survive longer and reproduce better than thrips that were not infected.

Asifa Hameed, who led the study while completing her doctoral degree in entomology at Penn State and is now a senior scientist of entomology at Ayub Agricultural Research Institute in Multan, Pakistan, said the findings give key insight into how the virus spreads in plants and affects its insect hosts.

“In addition to prolonging the life of the insects, SVNV infection also shortened the doubling time of soybean thrip populations,” Hameed said. “This means infected thrips populations grew much more quickly, which could enhance the spread of the virus to additional soybean plants.”

According to the researchers, who recently published their findings in the journal Insects, soybean vein necrosis is a disease that affects soybean plants and is caused by SVNV. It can be spread by either infected seeds or infected soybean thrips. The thrips contract the virus as larvae by feeding on infected leaves and then can pass the virus to additional plants through their saliva, mainly during thrips adulthood.

Once a plant is infected with the virus, the pathogen first attacks the veins of the leaves, causing them to turn yellow. This yellowing then can spread to other parts of the leaves, which eventually may develop brown lesions.

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Bats’ midnight snacks reveal clues for managing endangered

How do we bring threatened and endangered animals back from the brink? The task is never easy or simple, but one thing is undeniably true: If we don’t understand these animals and what they need to survive, we have little chance of success.

Saving bats, then, is arguably a trickier endeavor than for other species. After all, the cryptic critters only emerge at night and are highly mobile, making it difficult to track their movements and behavior.

In a first-of-its-kind study, University of Illinois and Brown University scientists reveal the diets of endangered Indiana bats and threatened northern long-eared bats, providing clues to effectively manage both species and their habitats.

“This was an in-depth study of these two imperiled species in landscapes where they co-occur. Nobody’s done that before. This investigation gives us a much better sense of how bats not only coexist, but also how they benefit our forests and how we can thus manage the forest to provide bats with better habitat,” says Joy O’Keefe, an assistant professor and wildlife extension specialist in the Department of Natural Resources and Environmental Sciences at Illinois.

Previous research into these bats’ diets relied on older, outdated technologies that could miss important prey species. And no study had yet investigated how the two species divvy up their prey resources to coexist.

“When you have two closely related species sharing the same habitat, that means they’re probably built similarly and need similar places to live and things to eat. This brings up a lot of questions about how they’re doing that. Are they competing? Or is there some system in place where they’re able to divide resources? Our job was to figure that out,” says Tim Divoll, a data scientist in the Center for Computation & Visualization at Brown who completed his doctoral

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Nanoplastics can move up the food chain from plants to

A new study from the University of Eastern Finland shows that lettuce can take up nanoplastics from the soil and transfer them into the food chain.

The concern about plastic pollution has become widespread after it was realised that mismanaged plastics in the environment break down into smaller pieces known as microplastics and nanoplastics. It is likely that nanoplastics, due to their small size, can pass through physiological barriers and enter organisms.

Despite the growing body of evidence on the potential toxicity of nanoplastics to plants, invertebrates and vertebrates, our understanding of plastic transfer in food webs is limited. For instance, little is known about nanoplastics in soil ecosystems and their uptake by soil organisms, despite the fact that agricultural soil is potentially receiving nanoplastics from different sources such as atmospheric deposition, irrigation with wastewater, application of sewage sludge for agricultural purposes, and use of mulching film. Measurement of uptake of nanoplastics from the soil by plants, particularly vegetables and fruit in agricultural soils, is thus a critical step to reveal whether and to what extent nanoplastics can make their way into edible plants and, consequently, into food webs.

Researchers at the University of Eastern Finland have developed a novel, metallic fingerprint-based technique to detect and measure nanoplastics in organisms and, in this new study, they applied it to a model food chain consisting of three trophic levels, i.e., lettuce as a primary producer, black soldier fly larvae as a primary consumer, and the insectivorous fish (roach) as a secondary consumer. The researchers used commonly found plastic waste in the environment, including polystyrene (PS) and polyvinyl chloride (PVC) nanoplastics.

Lettuce plants were exposed to nanoplastics for 14 days via contaminated soil, after which they were harvested and fed to insects (black soldier fly larvae, which are used as a source

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