Red Admiral Butterfly
Urban landscapes differ from rural landscapes primarily in continuity and size of patches. Rural landscapes have larger patches with greater continuity. Urban landscapes have smaller patches with less continuity. How do these factors influence pollinators?
In a study of flowers and pollinators*, citizen scientists photographed all pollinators at a single flower in a 20 minute period. The pollinators were classified into generalists and specialists. There were fewer taxa of urban pollinators and more of them were generalist pollinators. Rural landscapes had a greater diversity of pollinators and more specialist pollinators. Urbanization is major component of habitat loss for both plants and animals. Plant-pollinator interaction, especially plants that are pollinated by specialists, may be important factors in species loss and retention.
*Nicolas Deguines, Romain Julliard, Mathieu de Flores & Colin Fontaine. 2016. Functional homogenization of flower visitor communities with urbanization. Ecology and evolution. Vol.6: 1967-1976.
A Native Bee
Issues with honey bees such as colony collapse disorder have increased the cost of honey bee rentals to fruit growers and in some cases, pollination hives may be difficult to obtain. In the past, abundance of honey bees made it unnecessary to study the effects of native bee pollinators. The reduction in honey bee pollination services demands a better understanding of native pollinators.
A group of scientists* has investigated pollination by native bees in New York apple orchards. The numbers of seed per fruit (a measure of pollinators) was positively correlated with both wild bee abundance and the number of bee species. Honey bees did not fully compensate for absence of wild bees. This suggests that honey bees may be over rated and native bees under rated as pollinators of apple orchards. The follow up question, “How can apple growers actively maintain wild bee species richness and functional diversity in their orchards?” Obvious candidates are management of alternative food sources for periods when apples are not blooming and other landscape measures that promote bees. What are the best management practices? Further research is needed to answer the question.
*Eleanor J. Blitzer, Jason Gibbs, Mia G. Park, Bryan N. Danforth. Pollination services for apple are dependent on diverse wild bee communities. Agriculture, Ecosystems and Environment 221 (2016) 1–7.
Left: A fly samples the petals of a crocus
Right: A honey bee collects pollen from a crocus
When asked about pollinators, most people immediately think about bees. Bees use plant pollen as a protein source to feed their offspring and must visit flowers. Other insects may also feed on pollen and ingest it as a protein source to provision their eggs. These insects (non-bees) are also important pollinators.
A team of scientists* investigated pollination and observed that insects other than bees performed 25–50% of the total number of flower visits. The non-bees were found to be less efficient than bees, but compensated for the inefficiency with more flower visits. Non-bees make a substantial contribution to pollination of our food crops. Further, non-bees may respond to landscape management in a manner different than bees. Efforts to preserve and enhance pollinators should account for both bees and other insect pollinators.
*Romina Rader and colleagues. Non-bee insects are important contributors to global crop pollination
PNAS 2016 113 (1) 146-151; vol. 113 no. 1
Tiger Beetle is part of the Microsculpture exhibit. Image: Levon Biss
The Oxford University Museum of Natural History is promoting a new exhibit to open at the end of this month called “Microsculpture”. It features the work of photographer Levon Bliss who photographs insects through microscope lenses. He uses a stacking technique of 1 image every 10 microns. A stack may consist of thousands of images. He divides an insect into numerous sections (30 or more) and concentrates on one section at a time. Lighting is critical to the final image. The result is an image with incredible pixel density that allows a viewer to zoom in on some of the smallest details of each insect. For the Oxford exhibit, the images are printed as enormous posters that allows the viewer to stand in awe of the complexity and beauty of the insect form.
The video from the Microsculpture site is worth watching:
EPA Repellent Information
Women are especially concerned about health risks during pregnancy that could affect their child. Some chemicals and drugs are known to have adverse effects and are to be avoided. To be safe, many pregnant women try to avoid as many chemicals as possible. What about mosquito repellents? Should they be avoided? This question becomes more important as Zika virus spreads. The bottom line: There should be no worry about repellent use. The worry should be about NOT using repellent. Exposure to Zika is a far greater risk than repellent use.
Mosquito repellents are safe for pregnant women when used according to directions. There are no documented cases of adverse effects or other harm to babies born to mothers who used mosquito repellents. In areas where Zika is spread, the risk of harm from Zika can be greatly reduced by using repellents. The Environmental Working Group has a useful guide to repellents that compares effectiveness. Repellents have labels that indicate effectiveness of the product. Chose a product that is effective. “Natural” products are not necessarily “safer” than scientifically designed products.
As always, guidelines for repellent use should be followed. When indoors, repellent can be washed from the skin with soapy water. Repellents can be used to treat clothing as well as skin. Covering the skin and avoiding areas with high mosquito populations is advisable. Window screens and measures that prevent mosquito entry indoors are a must.
The Yellow Jacket is responsible for more stings than any other Indiana wasp.
Over 90% of residents of the US report being stung by an insect before reaching adulthood. Most people are unable to accurately identify the insect responsible. Accurate identification is important to people who have an allergic reaction to an insect sting so they can avoid repeated stings. Allergists want to know the identity of the insect that caused the reaction as part of the patient education.
A group of scientists tested the ability of allergists and random individuals to recognize 4 types of stinging insects: honey bee, yellow jacket, paper wasp and hornet. Ninety percent of allergists and non-allergists correctly identified honey bees from pictures, but fewer than half correctly identified dried specimens. Allergists were better at identifying Hornets and Yellow jackets from pictures than non-allergists. In most cases, people were able to identify the insects from pictures with more accuracy than from dried specimens.
How does this affect allergy treatment? Many people with sting allergies fail to get a close look at the insect. Those that do may misidentify it. It is common practice for allergists to test a suite of insect venoms on patients with allergies. Cross reaction to venoms is common and this practice helps identify multiple allergies. The identity of the insect is not as important to the characterization of the allergy as it is to the education of the patient on avoiding future stings. This study suggests that the need for improvements to teaching identification of stinging insects.
*Troy W. Baker; Joseph P. Forester; Monica L. Johnson; Jeremy M. Sikora; Adrienne Stolfi & Mark C. Stahl. Stinging insect identification: Are the allergy specialists any better than their patients? Ann Allergy Asthma Immunol. (2016) 1-4.
The US-EPA is issuing draft reports for public comment on the effects of pesticides on endangered species. Three organophosphate insecticides, chlorpyrifos, malathion and diazinon are the first pesticides studied. The potential for effects on endangered species from these pesticides is high, because of use as mosquito adulticides. Thus, there may be some trade offs between endangered species protections and efforts to protect the public from mosquito vectored diseases.
Good mosquito control typically targets larval populations as the first line of defense. If done properly, adulticides can be avoided, thus avoiding potential conflict. If these chemicals are used as adulticides, more consideration of effects on non-target species and new rules to minimize those effects are likely next steps.