2016-12-24T18:13:07

Aim Temporal dynamics of biodiversity along tropical elevational gradients are unknown. We studied seasonal changes of Lepidoptera biodiversity along the only complete forest elevational gradient in the Afrotropics. We focused on shifts of species richness patterns, seasonal turnover of communities and seasonal shifts of species’ elevational ranges, the latter often serving as an indicator of the global change effects on mountain ecosystems. Location Mount Cameroon, Cameroon. Taxon Butterflies and moths (Lepidoptera). Methods We quantitatively sampled nine groups of Lepidoptera by bait‐trapping (16,800 trap‐days) and light‐catching (126 nights) at seven elevations evenly distributed along the elevational gradient from sea level (30 m a.s.l.) to timberline (2,200 m a.s.l.). Sampling was repeated in three seasons. Results Altogether, 42,936 specimens of 1,099 species were recorded. A mid‐elevation peak of species richness was detected for all groups but Eupterotidae. This peak shifted seasonally for five groups, most of them ascending during the dry season. Seasonal shifts of species’ elevational ranges were mostly responsible for these diversity pattern shifts along elevation: we found general upward shifts in fruit‐feeding butterflies, fruit‐feeding moths and Lymantriinae from beginning to end of the dry season. Contrarily, Arctiinae shifted upwards during the wet season. The average seasonal shifts of elevational ranges often exceeded 100 m and were even several times higher for numerous species. Main conclusions We report seasonal uphill and downhill shifts of several lepidopteran groups. The reported shifts can be driven by both delay in weather seasonality and shifts in resource availability, causing phenological delay of adult hatching and/or adult migrations. Such shifts may lead to misinterpretations of diversity patterns along elevation if seasonality is ignored. More importantly, considering the surprising extent of seasonal elevational shifts of species, we encourage taking account of such natural temporal dynamics while investigating the global climate change impact on communities of Lepidoptera in tropical mountains.

Aim The distribution of neotropical butterflies of the tribe Pronophilini (Lepidoptera, Satyridae) was analysed with the aim of determining (i) the elevational ranges of distribution of each species (ii) the elevational gradient in diversity, and (iii) the existence of parapatric distributions of some closely related species pairs. Location The field study was carried out in the middle and upper section of the valley of the Río Albarregas, a tributary of the Río Chama on the southern slopes of the Serranía de la Culata, in the central part of the Cordillera de Mérida, Venezuela. Methods The material was collected along an elevational transect set on a trail leading from Merida to the Páramo de Los Conejos in the area known as Monte Zerpa. It consisted of a series of 32 collection sites set at every 25 m of altitude and covered an elevation from 2250 m to 3025 m. Results The ranges of Lymanopoda obsoleta, L. albocincta, L. zapatoza, Corades chelonis, C. pannonia, C. medeba, Mygona irmina, Pedaliodes epidipnis, P. japhleta, P. montagna and P. panyasis were all restricted to the lower half of the cloud forest zone and L. diezti, C. pax, P. polla, P. ornata and P. ferratilis were all restricted to the upper part. Two species, Erethris porphyria and Steroma bega, crossed the entire elevational range of the cloud forest zone.The biodiversity, as measured by Shannon’s index, attained a maximum at 2700 m, beyond which it gradually decreased. A parapatric distribution was confirmed for three pairs of closely related species: L. obsoleta and L. diezti, C. chelonis and C. pax and P. montagna and P. ferratilis. Main conclusions The peak in diversity at middle elevations seems to result from the overlapping ranges of species distributed over lower and upper parts of the cloud forest. Correlation of species composition at particular transect sites with elevation showed that increase in elevation was associated with an increase in species composition difference. Post‐mating isolation was suggested as a primary factor responsible for maintaining the parapatric distributions of species occupying the upper and lower zones and preventing their respective distributions from expanding.

Although seasonality in the tropics is often less pronounced than in temperate areas, tropical ecosystems show seasonal dynamics as well. Nevertheless, individual tropical insects’ phenological patterns are still poorly understood, especially in the Afrotropics. To fill this gap, we investigated biodiversity patterns of Lepidoptera communities at three rainforest localities in the foothills of Mount Cameroon, West Africa, one of the wettest places in the world. Our multitaxa approach covered six lepidopteran groups (fruit‐feeding butterflies and moths, the families Sphingidae, Saturniidae, and Eupterotidae, and the subfamily Arctiinae of Erebidae) with diverse life strategies. We sampled adults of the focal groups in three distinct seasons. Our sampling included standardized bait trapping (80 traps exposed for 10 days per locality and season) and attraction by light (six full nights per locality and season). Altogether, our dataset comprised 20,576 specimens belonging to 559 (morpho)species of the focal groups. The biodiversity of Lepidoptera generally increased in the high‐dry season, and either increased (fruit‐feeding moths, Arctiinae, Saturniidae) or decreased (butterflies, Sphingidae) in the transition to the wet season in particular groups. Simultaneously, we revealed a strong species turnover of fruit‐feeding Lepidoptera and Arctiinae among the seasons, indicating relatively high specialization of these communities for particular seasons. Such temporal specialization can make the local communities of butterflies and moths especially sensitive to the expected seasonal perturbations caused by the global change. Because of the key role of Lepidoptera across trophic levels, such changes in their communities could strengthen this impact on entire tropical ecosystems.

Species distributions are a product of contemporary and historical forces. Using phylogenetic and geographic data, we explore the timing of and barriers to the diversification of the Andean butterfly genus Lymanopoda (Nymphalidae, Satyrinae). Clade and species level diversification is coincident with Andean orogeny and Pleistocene glaciation cycles. Lymanopoda has primarily diversified within elevational bands, radiating horizontally throughout the Andes with occasional speciation across elevational boundaries, often associated with ecotones. Narrow elevational ranges and infrequent speciation into adjacent elevational strata suggest that expansion across elevational gradients is relatively difficult. These results are similar to those found in studies of other Andean taxa.