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The evolutionary transition between winglessness and a full-winged morphology requires selective advantage for intermediate forms. Conversely, repeated secondary wing reductions among the pterygotes indicates relaxation of such selection. However, evolutionary trajectories of such transitions are not well-characterized. The stick insects (Phasmatodea) exhibit diverse wing sizes at both interspecific and intersexual levels, and thus provide a system for examining how selection on flight capability, along with other selective forces, drives the evolution of flight-related morphology. Here, we examine variation in relevant morphology for stick insects using data from 1,100+ individuals representing 765 species. Although wing size varies along a continuous spectrum, taxa with either long or miniaturized wings are the most common, whereas those with intermediate-sized wings are relatively rare. In a morphological space defined by wing and body size, the aerodynamically relevant parameter termed wing loading (the average pressure exerted on the air by the wings) varies according to sex-specific scaling laws; volant but also flightless forms are the most common outcomes in both sexes. Using phylogenetically-informed analyses, we show that relative wing size and body size are inversely correlated in long-winged insects regardless of sexual differences in morphology and ecology. These results demonstrate the diversity of flight-related morphology in stick insects, and also provide a general framework for addressing evolutionary coupling between wing and body dimensions. We also find indirect evidence for a "fitness valley" associated with intermediate-sized wings, suggesting relatively rapid evolutionary transitions between wingless and volant forms.

Carrion is a rich, ephemeral resource vital to biodiversity and ecosystem health. In temperate ecosystems in which cold temperatures and snowfall influence the accessibility and availability of small prey and seasonal mast crops, carrion may also be a limiting resource for mesocarnivores like red foxes (Vulpes vulpes), which are too small to predate ungulates. Using motion-triggered video cameras and generalized linear mixed models, we studied the spatial and temporal patterns of red fox scavenging at 232 mountain lion kills in the southern Greater Yellowstone Ecosystem (GYE) from 2012–2015. We found that red foxes scavenged mountain lion kills across all habitats throughout the year, however, red fox behaviors varied with season. In winter, we documented red foxes at a greater proportion of mountain lion kills (70.3% in winter vs. 48.9% in summer), and in greater numbers (1.83 foxes per kill in winter vs. 1.16 in summer). In winter, red foxes fed longer (= 102.7 ± 138.3 minutes feeding in winter vs. = 39.7 ± 74.0 in summer), and they more often scavenged while the mountain lion was nearby. We speculated that red foxes may have increased risk taking in winter due to hunger driven by resource scarcity. Our research highlighted an important ecological relationship between red foxes and mountain lions in the GYE. Mountain lions tolerate high levels of scavenging, so the frequency and intensity of red fox scavenging at their kills may not impact mountain lions, but instead facilitate the dispersion and benefits of resources created by this apex predator. Large carnivores, and mid-trophic felids like mountain lions in particular, are essential producers of carrion vital to biodiversity and ecosystem health. In turn, scavengers play critical roles in distributing these resources and increasing the heterogeneity of resources that support biodiversity and ecosystem structure, as well as ecological resilience.

Hunting results in direct numerical effects and numerous indirect effects on game species. One indirect effect occurs when a female is killed; and as a consequence, her dependent offspring die, negatively affecting recruitment rates. The mountain lion (Puma concolor) is a hunted species across much of its range. It is almost always illegal to harvest a female with dependent young; however, females frequently travel separately from their kittens, and the occasional unintentional harvest of females with dependent young is unavoidable. We studied the denning periods for female mountain lions in northwest Wyoming, USA, from June 2001 to December 2016, but more intensively between January 2013 and December 2016 with Global Positioning System (GPS) technology. During the intensive period, we measured the amount of time females spent away from the den, distance and time females traveled during each foraging trip, and distance traveled during the entire denning period. We also compared the timing of dens with mountain lion hunting seasons. We recorded parturition dates between 6 June and 4 November. On average, females utilized 4.2 ± 0.5 (SE) dens/denning period, with denning periods persisting 45.8 ± 2.6 (SE) days. The average total distance traveled by females during their 6‐week denning period was 154 km (±18.8 km). On average, females were closest or most likely to be with their kittens at 1600, and furthest from den sites at 0200 and 0600. Utilizing our mean denning period of 46 days, delaying mountain lion hunting until 1 November would avoid the denning period for 85% of dens, and delaying until 1 December would avoid 91% (n = 31). Our research provides information to guide managers in aligning hunting seasons to mitigate orphaning kittens when they are youngest and most vulnerable, and provide hunters the best opportunities to detect and protect dependent young. © 2018 The Wildlife Society.

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