Abstract The responses of ectotherm growth and developmental rates to temperature depend on the duration of exposure and development stage. These rates determine fitness responses to climate change and variability and are subject to selection, potentially leading to evolutionary change. We repeat a study of thermal sensitivity of larval growth rates in a population of the cabbage white butterfly (Pieris rapae) to assess evolutionary responses to 25 years (more than 75 generations) of climate change. Modern caterpillars grow faster, particularly at warm temperatures that have become more prevalent in recent decades. Growth rate increases are most pronounced at shorter exposure durations and earlier in larval development. Our study points to the potential for contemporary evolution consistent with a response to recent climate change in a widespread and dispersive species.
Abstract Anthropogenic change is a near-universal pressure that impacts wildlife across the globe, yet organismal responses to multiple human-driven selective pressures remain poorly understood. Urbanization and hurricanes impose conflicting demands on the locomotor morphology of Anolis lizards, with urban habitats favouring longer limbs and larger toepads, whereas hurricanes select for larger toepads but shorter hindlimbs. Using forest and urban populations of the Puerto Rican crested anole (Anolis cristatellus), we asked whether adaptation to cities entails a cost to clinging performance in hurricane conditions. We measured sprint speed and high wind clinging duration in each individual and used X-ray imaging to identify the skeletal basis of each performance. We found that sprint speed and clinging duration were positively correlated in forest populations but uncorrelated in urban populations, representing a decoupling of ancestral integration in the city. Sprint speed was influenced by variation in limb morphology, whereas clinging performance was relatively insensitive to morphological variation, suggesting that these two performance axes are governed by distinct phenotypes. Taken together, these findings highlight the importance of understanding anthropogenic adaptation as an integrated composite of distinct but interacting forces, with response to selection along one axis potentially constraining adaptive response to another.
Abstract Many marine invertebrates exhibit high variation in body coloration that can serve different adaptive functions, including camouflage. In many animals, effective concealment is a three-way interaction between body appearance, behaviour, and the substrate. However, it is generally not well understood in many animals how camouflage is achieved in individuals when there exists high, but fixed, intraspecific variation in coloration. Here, we tested whether variation in coloration and background choice of common cushion stars, Asterina gibbosa, can provide them with effective background matching. We used digital photography to quantify objectively the coloration of starfish and substrates in their intertidal environment and the match between starfish and preferred and non-preferred substrates. We demonstrated that starfish generally match their preferred substrate type (usually undersides and sides of boulders) more closely than other potential substrates and have continuous variation in coloration among individuals. Furthermore, we tested experimentally whether starfish actively selected a background type that individuals matched better. Regardless of individual coloration, starfish preferred dark over light experimental gravel type but showed no preferences between green and orange gravel. Our results indicate that starfish coloration and behaviour are likely to function both in camouflage and in finding shelters, but further work is needed to establish the function, if any, of variation in colour types.
Abstract Neotropical Malpighiaceae flowers produce oil as a main and essential resource for most bees of the Centridini, Tapinotaspidini, and Tetrapediini tribes. Interactions between these flowers and floral visitors form networks structured along a specialization–generalization continuum. However, network structure may vary with flowering seasonality and visitor behaviour, including pollinators and thieves. Here, we provide the first quantitative assessment of seasonal changes in Malpighiaceae-floral visitor networks, incorporating different functional roles. All networks were significantly modular and specialized, but not nested, indicating a structured yet non-hierarchical organization. Network structure shifted across seasons and functional roles, suggesting that the balance between mutualistic and antagonistic interactions is dynamically reorganized over time. Contrary to expectations, networks were not primarily structured by oil-specialist bees. Instead, generalist Meliponini bees played central roles in maintaining connectivity, whereas oil-bees were less influential, with only a single Epicharis species contributing to modularity. The predominance of peripheral species and few highly connected nodes indicate limited functional redundancy, potentially increasing vulnerability to species loss. Overall, our findings show that Malpighiaceae networks are driven by the interplay between generalist and specialist species, emphasizing the importance of including antagonistic interactions to understand ecological network organization and stability.
Abstract Although cryptic species are known to lead to underestimates of biodiversity, cryptic genera may present greater challenges for evolutionary studies. Surprisingly, there remain long-standing groups that contain unrecognized polyphyly due to extreme similarity in morphology and lifestyle. A good example is the large frog genus Oreophryne whose monophyly was never questioned in its 130-year history. Recently, by using dense taxonomic sampling across the microhylid subfamily Asterophryinae, our group has shown it to be composed of two non-sister monophyletic clades. Here we show that the two arboreal clades are morphologically undiagnosable and define them using phylogenetic taxonomy. We include the type species O. senckenbergiana (=O. moluccensis), resolving which clade retains the name Oreophryne, and name the strikingly similar genus Auparoparo gen. nov. from the indigenous Papuan language Motu. Their geographical distributions implicate plate tectonic activity in diversification, with Oreophryne distributed from the Philippines to Indonesia, along central to south New Guinea and its satellite islands, whereas Auparoparo occurs in Sulawesi and southern New Guinea and satellite islands where there is range overlap. As evidenced by this case, groups with unrecognized polyphyly are still in use today, so we urge careful confirmation of monophyly for a nomenclature based on evolution that will promote sound evolutionary research.
