Ecology and Evolutionary Biology Commons^™

Cold Shock Induces A Terminal Investment Reproductive Response In C. Elegans, Leah Gulyas, Jennifer R. Powell

Biology Faculty Publications

Challenges from environmental stressors have a profound impact on many life-history traits of an organism, including reproductive strategy. Examples across multiple taxa have demonstrated that maternal reproductive investment resulting from stress can improve offspring survival; a form of matricidal provisioning when death appears imminent is known as terminal investment. Here we report a reproductive response in the nematode Caenorhabditis elegans upon exposure to acute cold shock at 2 °C, whereby vitellogenic lipid movement from the soma to the germline appears to be massively upregulated at the expense of parental survival. This response is dependent on functional TAX-2; TAX-4 cGMP-gated channels …

Heterotrophic Carbon Fixation In A Salamander-Alga Symbiosis, John A. Burns, Ryan Kerney, Solange Duhamel

Biology Faculty Publications

The unique symbiosis between a vertebrate salamander, Ambystoma maculatum, and unicellular green alga, Oophila amblystomatis, involves multiple modes of interaction. These include an ectosymbiotic interaction where the alga colonizes the egg capsule, and an intracellular interaction where the alga enters tissues and cells of the salamander. One common interaction in mutualist photosymbioses is the transfer of photosynthate from the algal symbiont to the host animal. In the A. maculatum–O. amblystomatis interaction, there is conflicting evidence regarding whether the algae in the egg capsule transfer chemical energy captured during photosynthesis to the developing salamander embryo. In experiments …

The Influence Of Signaling Conspecific And Heterospecific Neighbors On Eavesdropper Pressure, Paula A. Trillo, Christopher S. Benson, Michael S. Caldwell, Tiffany L. Lam, Oliver H. Pickering, David M. Logue

Biology Faculty Publications

The study of tradeoffs between the attraction of mates and the attraction of eavesdropping predators and parasites has generally focused on a single species of prey, signaling in isolation. In nature, however, animals often signal from mixed-species aggregations, where interactions with heterospecific group members may be an important mechanism modulating tradeoffs between sexual and natural selection, and thus driving signal evolution. Although studies have shown that conspecific signalers can influence eavesdropper pressure on mating signals, the effects of signaling heterospecifics on eavesdropper pressure, and on the balance between natural and sexual selection, are likely to be different. Here, we review …

Predicting The Future: Parental Progeny Investment In Response To Environmental Stress Cues, Leah Gulyas, Jennifer R. Powell

Biology Faculty Publications

Environmental stressors can severely limit the ability of an organism to reproduce as lifespan is decreased and resources are shifted away from reproduction to survival. Although this is often detrimental to the organism’s reproductive fitness, certain other reproductive stress responses may mitigate this effect by increasing the likelihood of progeny survival in the F1 and subsequent generations. Here we review three means by which these progeny may be conferred a competitive edge as a result of stress encountered in the parental generation: heritable epigenetic modifications to nucleotides and histones, simple maternal investments of cytosolic components, and the partially overlapping phenomenon …

Leonardo And The Whale, Kay Etheridge

Biology Faculty Publications

Around 1480, when he was 28 years old, Leonardo da Vinci recorded what may have been a seminal event in his life. In writing of his travels to view nature he recounted an experience in a cave in the Tuscan countryside:

Having wandered for some distance among overhanging rocks, I can to the entrance of a great cavern... [and after some hesitation I entered] drawn by a desire to see whether there might be any marvelous thing within..."

[excerpt]

Mating Patterns And Post-Mating Isolation In Three Cryptic Species Of The Engystomops Petersi Species Complex, Paula A. Trillo, Andrea E. Narvaez, Santiago R. Ron, Kim L. Hoke

Biology Faculty Publications

Determining the extent of reproductive isolation in cryptic species with dynamic geographic ranges can yield important insights into the processes that generate and maintain genetic divergence in the absence of severe geographic barriers. We studied mating patterns, propensity to hybridize in nature and subsequent fertilization rates, as well as survival and development of hybrid F₁ offspring for three nominal species of the Engystomops petersi species complex in Yasuní National Park, Ecuador. We found at least two species in four out of six locations sampled, and 14.3% of the wild pairs genotyped were mixed-species (heterospecific) crosses. We also found reduced …

Linking Snake Behavior To Nest Predation In A Midwestern Bird Community, Patrick J. Weatherhead, Gerardo L.F. Carfagno, Jinelle H. Sperry, Jeffrey D. Brawn, Scott K. Robinson

Biology Faculty Publications

Nest predators can adversely affect the viability of songbird populations, and their impact is exacerbated in fragmented habitats. Despite substantial research on this predator-prey interaction, however, almost all of the focus has been on the birds rather than their nest predators, thereby limiting our understanding of the factors that bring predators and nests into contact. We used radiotelemetry to document the activity of two snake species (rat snakes, Elaphe obsoleta; racers, Coluber constrictor) known to prey on nests in Midwestern bird communities and simultaneously monitored 300 songbird nests and tested the hypothesis that predation risk should increase for nests when …

Aquatic Ascomycetes From Lake Itasca, Minnesota, A. R. Cavaliere

Biology Faculty Publications

A preliminary report of the aquatic Ascomycetes of Lake Isasca, Minnesota. Included is an introduction, methods of harvesting and studying, a key, description, and illustrations of 19 common ascomycetous fungi inhabiting the study area.