News, Publications, Apps, & More
Bird Predation Depends on Caterpillar Appearance
Biologists at UC Irvine and Wesleyan University have found that caterpillars that feed only on one or two plant species are less visible to predatory birds than caterpillars that eat from a wide variety of plants. This is due to the fact that some caterpillars have evolved to adopt the coloration of the primary host plant that they consume, while generalist caterpillars may be more brightly colored. This evolutionary trait not only affects the caterpillars but also the plants: species consumed by the generalist caterpillars benefit because many caterpillars are removed by birds. Plants eaten by “specialist” caterpillars don’t benefit as much because birds do not target them.
Bee Diversity Improves Profits
Researchers from North Carolina State University have found that blueberry fruit size and production increase when flowers are pollinated by more diverse bee species. They identified 5 groups of pollinators within the test fields: honey bees, bumble bees, carpenter bees, and 2 groups of native bees. The economic benefits of pollination by more than one group are huge: for each additional group, the increase in yield was approximately $300 per acre. They believe the benefit comes from the differe nces in behavior between bee groups, especially in relation to the weather. With diverse species being active at different times, it is possible for continuous pollination to occur.
Habitat Fragmentation Leads to Disease Susceptibility
A new Finland fungal epidemiology study in Science has found that proximity to other meadows increases disease resistance in wild meadow plants. More than 4,000 meadows were surveyed over the last 13 years, looking at the infection rate of powdery mildew in comparison to the surrounding area. The study shows that disease resistance has increased in areas where there is more gene flow between plant populations. This is a strong demonstration that landscape structure determines how seed and pollen travel, shaping the genetic diversity of populations.
Males Win in Hotter Climates
Scientists out of the University of Montreal have discovered that weather plays a role in the gender of insect offspring. The study looked at a parasitoid wasp, Trichogramma euproctidis, whose fertilized eggs produce females and unfertilized eggs produce males. Their research found that when the wasps parasitized prey in hot weather and in sunny areas, more males were produced. When they parasitized prey in cool weather or shady areas, more females were produced. The scientists theorize that with the advance of climate change, there could be an “asynchrony" between parasitoids and their hosts, and therefore an impact on the availability of host eggs and on pest control by their natural enemies.
Spider Venom Safe for Bees
A new insecticide made from the Australian funnel web spider venom and a snowdrop's plant protein has been found to be safe for honey bees yet highly toxic to a number of insect pests. Feeding large doses to honey bees, much higher levels than they would experience in the field, had a very slight effect on the bee survival rate and no effect on learning or memory. Previous studies have also shown that the chemical is safe for mammals, and therefore has potential to be a new biopesticide.
Social Spiders Adopt Roles
Researchers investigated the social roles of the comb-footed spider and found that there are two kinds of females in this species: aggressive and docile. Aggressive females tend to attack prey and invaders while docile females don’t. Docile females care for offspring three times as much as aggressive spiders. The study found that colonies with a mixture of aggressive and docile females perform better than those with just one or the other. These new findings shed light on how differences in personality can help divide up labor in species.
Useful Publications and Websites
The Pollinator-Friendly Seed Directory is a comprehensive list of companies that sell organic seeds to the general public.
Farming with Native Beneficial Insects out of Storey Publishing is a new book that includes insect biology and identification, and shows how to create a farm or garden habitat that will attract beneficial insects.
The National Pesticide Information Center has released 2 new apps: Pesticide Education and Search Tool (PEST) and Mobile Access to Pesticides and Labels (MAPL).
Biological Control of Plant-Parasitic Nematodes is newly published book that focuses on integrated soil biology management and ways to increase the activity of natural enemies and use soil biological processes to reduce losses from nematodes.