Taxa may respond differently to climatic changes, depending on phylogenetic or ecological effects, but studies that discern among these alternatives are scarce. Here, we use two species pairs from globally distributed spider clades, each pair representing two lifestyles (generalist, specialist) to test the relative importance of phylogeny versus ecology in predicted responses to climate change. We used a recent phylogenetic hypothesis for nephilid spiders to select four species from two genera (Nephilingis and Nephilengys) that match the above criteria, are fully allopatric but combined occupy all subtropical-tropical regions. Based on their records, we modeled each species niche spaces and predicted their ecological shifts 20, 40, 60, and 80 years into the future using customized GIS tools and projected climatic changes. Phylogeny better predicts the species current ecological preferences than do lifestyles. By 2080 all species face dramatic reductions in suitable habitat (54.8-77.1%) and adapt by moving towards higher altitudes and latitudes, although at different tempos. Phylogeny and life style explain simulated habitat shifts in altitude, but phylogeny is the sole best predictor of latitudinal shifts. Models incorporating phylogenetic relatedness are an important additional tool to predict accurately biotic responses to global change.
COBISS.SI-ID: 37178413
The knowledge on species’ habitat preferences at local scales across its range is an essential condition for defining the most appropriate habitat management for the conservation of any species. We combined field observations from three European countries with breeding experiments under field conditions to identify oviposition and larval preferences of Coenonympha oedippus at the micro-scale level across a large spatial scale and contrasting habitat types (wet vs. dry). Despite the wide geographical range and the different habitats we found some common features: (1) vegetation structure of the herb layer is an essential factor for oviposition site electivity and successful development of premature stages; (2) high cover of litter and/or dwarf shrubs in the microhabitat creates a herb layer rich in gaps; at their edges eggs are deposited and the caterpillars are adequately sun-exposed; (3) egg-laying females are not selective regarding oviposition substratum; (4) oviposition height is adjusted to positions with direct sunlight or warm substratum; (5) the host-plants coverage in oviposition sites was high (cca. 40%); (6) the most important host-plant is Carex panicea (wet) and Carex humilis (dry); (7) the availability of winter-green host-plants in the vicinity of hibernated larvae plays a substantial role in their survival. Based on the results from field observations and breeding experiments we proposed the implications for habitat management of this highly endangered species in Europe.
COBISS.SI-ID: 37824557
Urbanization poses serious extinction risks, yet some species thrive in urban environments. This may be due to a pronounced developmental plasticity in these taxa, since phenotypically plastic organisms may better adjust to unpredictable urban food resources. We studied phenotypic plasticity in Nuctenea umbratica, a common European forest and urban vegetation spider. We subjected spiderlings to different food treatments and documented their growth and developmental trajectories into adulthood. Nuctenea umbratica exhibited elements of both canalization and plasticity in growth and developmental trajectories. While they are unconstrained in developmental time (in the laboratory) enabling them to achieve maximal mass and size – main fitness proxies – in given conditions, the relatively fixed growth ratio and long generation turnover may be the reasons for their relatively lower success in the urban environments when compared with urban achievers such as Zygiella and Larinioides.
COBISS.SI-ID: 37178669
Sexual dimorphism describes substantial differences between male and female phenotypes. In spiders, sexual dimorphism research almost exclusively focuses on size, and recent studies have recovered steady evolutionary size increases in females, and independent evolutionary size changes in males. Their discordance is due to negative allometric size patterns caused by different selection pressures on male and female size (converse Rensch’s rule). Here, we investigated macroevolutionary patterns of sexual size dimorphism (SSD) in Argiopinae, a global lineage of orb weaving spiders with varying degrees of SSD. We devised a Bayesian and maximum likelihood molecular species level phylogeny, then used it to reconstruct sex specific size evolution, to examine general hypotheses and different models of size evolution, to test for sexual size coevolution, and to examine allometric patterns of SSD. Our results, revealing ancestral moderate sizes and SSD, failed to reject the Brownian motion model, which suggests a non-directional size evolution. Contrary to predictions, male and female sizes were phylogenetically correlated, and SSD evolution was isometric. We interpret these results to question the classical explanations of female-biased SSD via fecundity, gravity, and differential mortality. In argiopines, SSD evolution may be driven by these or additional selection mechanisms, but perhaps at different phylogenetic scales.
COBISS.SI-ID: 37591341
There are changes in the realized niches of species along environmental gradients, especially at the edge of their distribution where they become more specialized. A classical case is weeds of the Caucalidion alliance that spread with agriculture from the Fertile Crescent and thrive in a wide range of climates that differ from that prevailing in their native area. We used large data sets of vegetation collected in central Europe (3383 plots) and north-western Balkans (4505 plots) and used a co-occurrence species algorithm to calculate the specialist/generalist status of weed species. The change in the width of the ecological niches was tested using target species. Our assumptions were confirmed as the same characteristic species of Caucalidion weed vegetation in the north-western Balkans are more specialized in central Europe, where they occupy more basic habitats that vary less in terms of soil reaction. Testing niche theory using real data is especially important for nature conservation because specialists are more prone to decline in abundance or to go extinct.
COBISS.SI-ID: 36572973