Nearly 5,000 historical and contemporary specimen records of stoneflies (Plecoptera) from Illinois demonstrated that this fauna is highly imperiled, boding poorly for aquatic insect communities in North America and elsewhere. Losses include two extinctions of endemics and 20 extirpations of 77 total species, a rate of loss that is higher than for either mussels or fish in Illinois. Another 19 species (24.7%) were designated as critically imperiled, being known from five or fewer locations. Two families, Perlidae and Perlodidae, experienced the greatest number of losses. Species lost were mostly those with longer life cycles and direct egg hatch. Three historically hyperdiverse regions were identified and losses in all 14 natural divisions were documented. Large river habitats and historically prairie regions have experienced the greatest proportional losses of species. This scenario probably follows for Ephemeroptera, Trichoptera, and Odonata in the Midwest and in other areas with similar glacial and cultural histories.

Many aphids harbor a variety of endosymbiotic bacteria. The functions of these symbionts can range from an obligate nutritional role to a facultative role in protecting their hosts against environmental stresses. One such symbiont is “CandidatusSerratia symbiotica,” which is involved in defense against heat and potentially also in aphid nutrition. Lachnid aphids have been the focus of several recent studies investigating the transition of this symbiont from a facultative symbiont to an obligate symbiont. In a phylogenetic analysis ofSerratiasymbionts from 51 lachnid hosts, we found that diversity in symbiont morphology, distribution, and function is due to multiple independent origins of symbiosis from ancestors belonging toSerratiaand possibly also to evolution within distinct symbiont clades. Our results do not support cocladogenesis of “Ca. Serratia symbiotica” withCinarasubgenusCinaraspecies and weigh against an obligate nutritional role. Finally, we show that species belonging to the subfamily Lachninae have a high incidence of facultative symbiont infection.