American Society of Parasitologists, Day 4

These are my notes from talks I saw on Friday's sessions!

R Grunberg gave a very nice talk about whether parasite abundance (density) scales with body size (Damuth’s Law). Her data suggests not. But host body size comes into play: if you do that, the parasites follow Damuth's Law. How you feed and disperse tweaks the effect a little.

Janine Caira: This project started with a donation of a huge, awesome army ant collection. Over 500 species were associated with just one species of army ant – guests associated with the army. Lots of ectoparasites live on specific parts of specific species. This prompted a lot of outreach at her campus, around the tag line, “Be our guest.” Antu.uconn.edu

Jessica Light: surveyed parasites on property in South Texas, supported by East Foundation. Not many mammals in museum collections are from South Texas. #collectionsareessential Found 19 mammal species, about 70% parasitized. Tick borne diseases are particularly interesting.

Niyomi Wijerardena: pika parasites! Pikas have five very distinct lineages, but the endoparasites don’t track those lineages. What about the ectoparasites? Fleas don’t track those lineages either, suggesting ancient contact between pika populations that are not recorded in DNA.

Lijun Lu is doing transcriptome work on what makes snail resistant to infection by schistomes.

Lauren Bassett was looking at the genetics of a microsporidium that is a potential biocontrol for red invasive fire ants.

Maria Castillo is also studying protein expression related to schistosomiasis infection of the snails. Thioester containing proteins seem to be related to resistance to various kinds of infection.

Presidential lecture by Gerald (Jerry) Esch. Described three stories, each of decades long and filled with obstacles from fights, fallacies, and waiting for blind luck, to emphasize the long road that research faces. He ended saying, “What does the future hold? I don’t know. But neither did the researchers who founded the field of parasitology 150 years ago.”

Michael Zimmerman starts describing the mating system of bluegill sunfish, which has dominant alpha males and beta males, which perform “drive by insemination.” Parasites may contribute to the maintenance of these two forms. The alpha males had higher diversity and abundance of parasites than beta males or females.

Nicci Carpenter: Helminths reduce fitness in mosquito fish (Gambusia affinis, also known as the plague fish)mosquito fish. The nematodes reduce brood size, and parasite diversity reduces embryo size.

Victor Vidal Martinez: healthy ecosystems have more parasites. Studying parasites on the fish on the Mexican portion of the Gulf of Mexico, which are subject to pollutants. Saw a higher diversity of parasites off the Yucatan Peninsula, which is good! It indicates a a healthier ecosystem than in the rest of the Mexican region of the Gulf.

Isabel Caballero: Although the cestode species she studies are definitely inbred, they show no strong evidence of inbreeding depression.

Stephen Greiman (@sgreimanbio): what drives species interactions now and in the past? He points out that when you look at just the top ten museum for mammal species, there are literally millions of samples in just those ten institutions. Using next generation sequencing, he was able to use next generation DNA sequencing to identify known parasites in shrews. Different sequences were slightly better at resolving some groups than others.

Seth Bromage: Bluegill and pumpkinseed sunfish are about the same size, but very different parasite infection patterns. The same species, U. dispar, is bigger on bluegill. Seth filled his talk with speculation, because “It’s fun for me.”

P Robison: For fish, salinity is a major environmental factor that limits distribution. Guppies will tolerate salty water in an aquarium, but you never find them in any salty water in the wild. Metacercaria are very high near the range limit, but rare near the center of the distribution (further from ocean). Exposure to brackish water killed more fish, and resulted in a higher parasite load, for the guppies.

John Shea: How do horsehair worms find each other to reproduce in hosts? Blood borne parasites can potentially have miles of blood vessels to search. It looks like in aquariums, there is substantial luck involved. But it looks a little better in lower water depth, with more evidence of successful mate detection.

Justin Wilcox: Most parasitologists think most animals are parasites, but that is just a hunch. He tested the hypothesis that parasite diversity will be comparable to free living microbial communities, using  parasites in macaques and next generation sequencing. Diversity of parasites and free living species is comparable. And there is a lot of diversity in these macaques.

Matt Bolek: presenting work of master’s student Chelsie Pierce. How do amphibian tadpoles differ from the adults in their parasites? Tadpoles are herbivores, e.g., and adults are carnivores: very different parasite habitats. Tadpole size, just like adults, affects parasite communities. Difficult to compare species, because the tadpoles’ basic natural history is so different. But parasite life cycle strategies were major factors in determining community structure.

Charles Criscione: The goal is to try to work out mating systems in parasite systems in the wild, and the particular focus here is on inbreeding. We know little about the ecological drivers of parasite mating systems. Looking at gecko tapeworms, which probably have high inbreeding. But, as mentioned in Isabel’s talk, not evidence of inbreeding depression.

The day ended with a student/faculty mixer, which the organizers called “The Vortex.” It was a good  idea, although it might have done with a little more room.