ANDIV

ANDIV1: Diversity and key traits of moths along a large elevational gradient in a biodiversity hotspot

Lepidoptera are among the “big four” clades of holometabolous insects, and they play key roles as pollinators, defoliators and prey, yet factors determining their diversity in the tropics are poorly understood. In ANDIV1, the species-rich Lepidoptera clades Geometridae and Arctiinae are used as model groups to test hypotheses on diversity gradients. The two taxa are phylogenetically unrelated and differ in many traits such as body size and coloration. For the first time, moths will be sampled quantitatively (light trapping) along a nearly complete elevational gradient in the tropical Andes. A research collection with ca. 30,000 moth specimens and a DNA-barcode library with ca. 3,500 species will be established that will become available for long-term research. The data set allows us to analyze diversity patterns and to investigate changes in selected functional traits of the moths along the elevation gradient. Body mass will be quantified with new and innovative methods. We will use UV photography and automated segmentation software for image analysis and determination of morphometric traits for all species. The planned study will allow to compile a high-quality dataset (species level) and test major hypotheses on diversity gradients.

ANDIV2: Patterns and drivers of the elevational diversity of dung beetles and dung flies in the Peruvian Andes 

ANDIV2 studies patterns and drivers of the diversity of dung beetles and dung flies along the Peruvian elevational gradient. We test how diversity gradients are shaped by climate, food resource abundance and land area. Dung beetles and dung flies are ideal model taxa to test these hypotheses as they use a clearly defined food resources, which can be quantified and manipulated. Dung insects are sampled in all seasons with baited pitfall traps and identified with the help of DNA barcoding. By combining sound taxonomic identification with measurements of functional traits (thermal limits, body size and color, resource specialization), phylogenetic data and mesocosm experiments on dung decomposition, different mechanisms underlying diversity gradients are tested. In cooperation with ANDIV4, we analyze elevational changes in the microbiome of dung insects, which have been shown to benefit from mutualistic relationships with bacteria. In concert with all other ANDIV projects and in close collaboration with Peruvian cooperation partners, ANDIV2 will contribute to our understanding of the drivers of the holometabolous insects and their microbiomes.

ANDIV3: Diversity and biotic interactions of bees and wasps along a forest elevational gradient in the Peruvian Andes 

ANDIV3 will study diversity patterns and biotic interactions of bees and wasps along the Peruvian elevation gradient. Field observations and experiments on species richness, abundance, morphological and physiological traits, and mutualistic and antagonistic biotic interactions of bees and wasps will be combined with (meta)barcoding of functional groups, stored pollen and arthropod prey. Bee and wasp diversity, plant-pollinator and host-antagonist interactions will be studied with transect observations, traps nests and pan traps during the dry and wet season on 30 study sites. In cooperation with ANDIV4 the hidden interactions of bees and wasps with microbial communities will be assessed. The results will allow to test general hypotheses on the role of bottom-up resource limitation, top-down control and interactive effects of temperature and precipitation as drivers of biodiversity patterns. Together with the other three ANDIV projects on moth, dung insects and microbial communities this project will allow integrative data analyses to improve the understanding of drivers of holometabolous insect diversity, community assembly, traits and interaction networks.

ANDIV4: Elevational effects on insect-associated microbiomes 

The microbial world and its change along climatic gradients on mountains has received little attention. Particularly, the impact on microbes associated with insect taxa has so far not been systematically investigated along elevational gradients. In this, we investigate the microbiota associated with the host taxa of all four major groups of holometabolous insects (Hymenoptera, Coleoptera, Diptera and Lepidoptera). The goal of this project is to identify elevational effects on the composition and diversity of insect-associated bacterial gut microbiomes, as well as to analyze genomes to describe relevant mechanisms responsible for elevational restrictions and impacts on functions for the host. We will combine cultivation-independent screening methods through meta-barcoding and bioassays experiments coupled with genomics to verify and experimentally proof restrictions according to the observed distributions of hosts and microbes. Further we will investigate genomic gains and losses of microbial functions for insect hosts. Together with the other ANDIV projects, this study will contribute to our understanding of the drivers of insects and microbiome biodiversity and function along elevational gradients.