- Author: Kathy Keatley Garvey
French evolutionary biologist Etienne GJ Danchin will discuss that topic at a seminar on Monday, Nov. 20, hosted by the UC Davis Department of Entomology and Nematology.
The seminar is from 4:10 to 5 p.m. in Room 122 of Briggs Hall. It also will be on Zoom. The Zoom link:
Danchin, known for his work on genomics and adaptive molecular evolution, is with INRAE (French National Research Institute for Agriculture, Food and Environment) and is a senior scientist and scientific leader of the GAME team (Genomics and Adaptive Molecular Evolution) at ISA (Institut Sophia Agrobiotech), in Sophia-Antipolis, on the French Riviera.
"Root-knot nematodes are devastating plant parasites of worldwide importance. Interestingly, species that cause most damages reproduce entirely asexually," he writes in his abstract. "These nematodes are extremely polyphagous and have a wide geographic range. Theoretically, in the absence of sexual recombination animal species have lower adaptive potential and are predicted to undergo genome decay. To investigate how these species can be successful parasites on many hosts and in many places around the world, we have sequenced and analyzed their genomes. Out analysis confirmed these species are polyploid hybrids and the combination of several genotypes from different species might provide them with a general-purpose genotype. However, this does not explain how with a theoretically fixed genotype these species are able to overcome resistance genes or adapt to a new host. Therefore, we analyzed genomic variability across different populations and the possible mechanisms underlying genomic variations. In this presentation, I will provide an overview of our findings."
Etienne holds a doctorate in reproductive biology from the University of Paris (1980). He says on his website: "I am an evolutionary biologist working with genomes. I try to make biological sense of genomic singularities observed through comparative genomics. I have a special interest in plant parasites and I use bioinformatics as a tool to perform this research."
He lists his main research interests as:
- The impact of non tree-like evolution such as horizontal gene transfers and hybridization on species biology
- Evolution and adaptation of animals in the absence of sexual reproduction and the underlying mechanisms
- Genomic signatures of adaptation to a parasitic life-style
Seminar coordinator is Brian Johnson, associate professor, UC Davis Department of Entomology and Nematology. For Zoom technical issues, he may be reached at email@example.com. The list of seminars is posted here.
- Author: Karey Windbiel-Rojas
- Author: Elaine Lander
The CDC health advisory states “Veterinary formulations intended for use in large animals such as horses, sheep, and cattle (e.g., “sheep drench,” injection formulations, and “pour-on” products for cattle) can be highly concentrated and result in overdoses when used by humans. Animal products may also contain inactive ingredients that have not been evaluated for use in humans. People who take inappropriately high doses of ivermectin above FDA-recommended dosing may experience toxic effects.”
Incorrect use of any pesticide can lead to injury, negative health impacts, or severe illness. Be sure to always read and understand the label when using pesticides and only use them where specified on the label. As a reminder, disinfectants are pesticides too, and should be used properly to minimize health risks.
Visit our website for more information on pesticides in homes and landscapes. If you suspect that you or someone you know is experiencing serious illness due to pesticide exposure, contact the Poison Control hotline at 800-222-1222.
- Author: Amy Murillo
- Posted by: Elaine Lander
Backyard chickens are increasingly being raised as pets, for egg production, and for youth development and science projects. While raising chickens can be an interesting and economically beneficial activity, chickens and other fowl may also have pest problems. Chickens are natural hosts to a variety of arthropod pests (called ectoparasites), including mites, lice, and fleas which feed on chickens and use chicken coops as habitats. These pests may cause discomfort to birds and decrease their egg production. This article aims to help people who keep chickens understand and learn treatment options for the common ectoparasites that can affect their animals.
There are two main species of mite found in backyard chicken flocks: the northern fowl mite (NFM; Ornithonyssus sylviarum) and poultry red mite (PRM; Dermanyssus gallinae). Both mite species feed on blood. NFM live on chickens in the fluffy feathers of the vent region (Figure 2a). PRM live off the animal in cracks and crevices near the birds, such as on perches (Figure 2b), in nestboxes, or in coops. Mites can bite people but cannot survive or reproduce on human blood and will not infest human bodies. Learn more about biting mites in homes and other structures here.
Scaly leg mites (Knemidocoptes mutans) may also affect chickens. These mites are microscopic and identification must be confirmed by an expert. However, the signs of a scaly leg mite infestation are obvious and include scabby or crusty legs or feet (Figure 3). Scaly leg mites spread by direct contact between animals, so quarantining infested birds can limit infestations within a flock.
Lice, mites, and fleas also parasitize wild birds and rodents and could be introduced to flocks by wild animals or even by contaminated equipment or people. To reduce pests in backyard flocks, focus on good biosecurity, which includes all practices that help to prevent or reduce disease in your flock. New chickens should be quarantined for at least two weeks to avoid introducing parasites (or other diseases) to the flock, washing hands and boots should occur before visiting the flock, and chickens should be separated from other animals. Birds should also be examined for signs of pests regularly to catch infestations early, which are easier to deal with than a large outbreak.
Insects and mites are very susceptible to water loss, so using natural materials that cause desiccation can be highly effective for general control. One such compound is diatomaceous earth (DE). Food-grade DE can be mixed with clean play sand in containers to create dustbathing areas for birds. Dustbathing is a natural behavior chickens perform to keep their feathers clean. The addition of DE helps to suppress pest populations.
Insecticides can be an effective tool for pest control. Farm stores often sell sprays or dusts that can be applied directly to birds or to coops for insect control. It is important to always read and follow the label instructions to avoid poisoning birds, people, or other animals. Pests that live in the environment, such as poultry red mites and sticktight fleas, are trickier to control since they may not be visible on chickens.
Murillo AC, Mullens BA. 2016. Diversity and prevalence of ectoparasites on backyard chicken flocks in California. Journal of Medical Entomology. 53: 707-711. https://www.researchgate.net/publication/290211878_Diversity_and_Prevalence_of_Ectoparasites_on_Backyard_Chicken_Flocks_in_California
Veterinary Entomology website with pest resources for professionals and the public: https://www.veterinaryentomology.org/poultry
For more backyard poultry resources, check out: https://ucanr.edu/sites/poultry/Resources_335/Production/type/backyard/
- Author: Siavash Taravati
- Posted by: Elaine Lander
Human lice (singular “louse”) are parasitic insects found on people. Adult lice are small (about 1/8 inch (3 mm) long or less) wingless insects that move by crawling. There are three species of lice that exclusively feed on humans: the head louse, the body louse, and the crab or pubic louse.
The head louse (Pediculus humanus capitis) and the body louse (Pediculus humanus humanus) are members of the same species, but the crab (pubic) louse (Pthirus pubis) is from a different insect family. All are pests of public health importance. Treatment is usually prescribed by medical professionals and should be focused on the infested person and their belongings. Use the following descriptions to identify these pests and help your clients seek out proper care from medical professionals.
These lice have a short, round body (not elongated), with hairy tubercles (small, knobby projections of the body wall) on the abdomen. The front legs are shorter and slimmer than the middle and hind legs (Figure 1). Adults and eggs are usually found on pubic hairs but may sometimes be found on other areas of the body such as beards, mustaches, eyelashes, and underneath the arms.
Head louse vs. body louse
Unlike the crab louse, these lice have elongated bodies (Figure 1) and lack tubercles on their abdomen. Head and body lice look almost identical since they are members of the same species. Positive identification requires consideration of specific morphological and behavioral differences (see Table 1). Body lice are known to transmit serious human diseases such as epidemic typhus, trench fever, and louse-borne relapsing fever. Head lice are not known to be an effective vector of diseases even when a pathogen is found in the louse's body.
Human lice elimination involves removal of lice from human body as well as from clothing and living environments. A head lice infestation on a person should be managed by the client. Head lice can be removed with a lice comb or treated with special lice shampoo or lotions containing one or more active ingredients. Human lice have developed resistance to many over-the-counter products containing permethrin or other pyrethroids. Therefore, it is believed that the most effective head lice treatment products are the ones containing ivermectin or spinosad. Body lice can be killed by dry cleaning clothing and bed sheets. Also, vacuuming and treating carpets may improve body lice management especially when the infestation is heavy. Body lice infestations can also be managed by reducing crowding and improving body and clothing hygiene. Head lice infestations, however, are not associated with poor hygiene, at least in developed countries.
For more details about the head louse, including thorough management options and guidance, see the recently revised Pest Notes: Head Lice.
- Author: Ben Faber
Bright metallic colors, flitting from flower to flower. Wasps. And they are going after other wasp species and bees. It's hard being a bee.
These wasps are parasites, and like their namesake cuckoo birds, they lay their eggs in the nests of other species (wasps or bees in this case). Since the cuckoo wasps depend on trickery and camouflage to fool their hosts, you might expect them to be drab. Scientists have not figured out whether the bright colors serve any function, and it wasn't known until 2009 that the color is actually produced by light refracting through open spaces between six layers of cuticle in the wasps' exoskeletons.
Cuckoo wasps favor warm Mediterranean climates, and California is a center of cuckoo wasp biodiversity in North America – 166 species in CA and 230 in the US. Maybe because there are so many native bee species in California is the reason there are so many cuckoo wasp species. They are most active in dry, open areas between May and August, with adults foraging on flower nectar as they follow favored routes multiple times a day searching for solitary wasps and bees to parasitize.
Cuckoo wasps are classified in the family Chrysididae, in the order Hymenoptera, and they are sometimes called Gold Wasps, Emerald Wasps or Jewel Wasps. The family name comes from the Greek, chryso, meaning gold. Besides green, they come in red, blue and purple and the thick cuticle of their exoskeleton (they are described as “heavily armored”) is often “pitted.” The common name refers to their habit of depositing their eggs in other insects' nests; a strategy practiced by birds like the Old World Cuckoos and the New World Cowbirds. Some sweat bees look similar, but cuckoo wasps tend to be “chunkier.”
Cuckoo wasps, like the majority of bees and wasps, are solitary. In highly social species like honeybees and paper wasps, there is a caste system. Since the queen is the only female that lays eggs, she is the only one outfitted with an ovipositor. And, since part of their job is defense, the workers' vestigial ovipositors have been modified into stingers. Solitary wasps need ovipositors, and many (but not all) sources say that cuckoo wasps have lost the ability to sting.
Read and see more about cuckoo wasps: The Cuckoo Wasp: A gorgeous parasite by David Lukas
And Lynn Kimsey's blog: https://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=26461