Functional Value of Elytra Under Various Stresses in the Red Flour Beetle, \u3cem\u3eTribolium castaneum\u3c/em\u3e

Coleoptera (beetles) is a massively successful order of insects, distinguished by their evolutionarily modified forewings called elytra. These structures are often presumed to have been a major driving force for the successful radiation of this taxon, by providing beetles with protection against a variety of harsh environmental factors. However, few studies have directly demonstrated the functional significance of the elytra against diverse environmental challenges. Here, we sought to empirically test the function of the elytra using Tribolium castaneum (the red flour beetle) as a model. We tested four categories of stress on the beetles: physical damage to hindwings, predation, desiccation, and cold shock. We found that, in all categories, the presence of elytra conferred a significant advantage compared to those beetles with their elytra experimentally removed. This work provides compelling quantitative evidence supporting the importance of beetle forewings in tolerating a variety of environmental stresses, and gives insight into how the evolution of elytra have facilitated the remarkable success of beetle radiation

Predator cues have contrasting effects on lifespan of Pardosa milvina (Araneae: Lycosidae)

Volume: 43Start Page: 107End Page: 11

Veni, vidi, vici? Future spread and ecological impacts of a rapidly expanding invasive predator population

Abstract Economic and ecological consequences of invasive species make biological invasions an influential driver of global change. Monitoring the spread and impacts of non‐native species is essential, but often difficult, especially during the initial stages of invasion. The Jorō spider, Trichonephila clavata (L. Koch, 1878, Araneae: Nephilidae), is a large‐bodied orb weaver native to Asia, likely introduced to northern Georgia, U.S. around 2010. We investigated the nascent invasion of T. clavata by constructing species distribution models (SDMs) from crowd‐sourced data to compare the climate T. clavata experiences in its native range to its introduced range. We found evidence that the climate of T. clavata's native range differs significantly from its introduced range. Species distribution models trained with observations from its native range predict that the most suitable habitats in North America occur north of its current introduced range. Consistent with SDM predictions, T. clavata appears to be spreading faster to the north than to the south. Lastly, we conducted surveys to investigate potential ecological impacts of T. clavata on the diversity of native orb weaving spiders. Importantly, Trichonephila clavata was the most common and abundant species observed in the survey, and was numerically dominant at half of the sites it was present in. Our models also suggest that there is lower native orb weaver species richness and diversity closer to where T. clavata was initially found and where it has been established the longest, though human population density complicates this finding. This early study is the first to forecast how widely this spider may spread in its introduced range and explore its potential ecological impacts. Our results add evidence that T. clavata is an invasive species and deserves much more ecological scrutiny

Dissociation between seasonal prey availability and prey consumption in a generalist predator

Daily temperatures averaged between four data loggers<div><br></div><div>Pitfall counts of what were potential prey items, other Collembola, and Schizocosa spp.</div><div><br></div><div>Predator molecular gut-content results</div

Sound files for The wolf spider Pardosa milvina detects predator threat level using only vibratory cues

<p>Sound files</p> <p>Predators may inadvertently signal their presence and threat level by way of signals in multiple modalities. We used a spider, <em>Pardosa milvina</em>, known to respond adaptively to chemotactile predator cues (i.e., silk, faeces and other excreta) to evaluate whether it could also discriminate predation risk from isolated vibratory cues. Vibrations from its prey, conspecifics, and predators (<em>Tigrosa helluo</em> and <em>Scarites quadriceps</em>) were recorded and played back to <em>Pardosa</em>. In addition, we recorded predator vibrations with and without access to chemotactile cues from <em>Pardosa</em>, indicating the presence of prey. <em>Pardosa</em> did not appear to discriminate between vibrations from prey or conspecifics, but the response to predators depended on the presence of cues from <em>Pardosa</em>. Vibrations from predators with access to chemotactile cues from prey induced reductions in <em>Pardosa</em> activity. Predator cues typically occur in multiple modalities, but prey are capable of imperfectly evaluating predation risk using a limited subset of information.</p