INFLUÊNCIA DE VARIÁVEIS AMBIENTAIS NAS FUNÇÕES ECOLÓGICAS DE ESCARABEÍNEOS EM SISTEMAS DE USO DO SOLO NO CAPARAÓ CAPIXABA

As funções ecológicas realizadas pelos besouros escarabeíneos, ou “rola-bostas”, foram estudadas nos três principais sistemas de uso do solo da região do Caparaó Capixaba: lavouras de café, pastagens e fragmentos florestais. Nos ambientes de florestas foi observada uma maior quantidade média de fezes enterradas em relação aos cafezais, já nas pastagens não houve diferenças significativas com os demais sistemas de uso do solo. As correlações entre as variáveis ambientais e as funções ecológicas estudadas puderam nos mostrar a influência da composição do solo e do tipo de vegetação sobre o enterrio de fezes e revolvimento do solo realizados pelos besouros. A complexidade da vegetação, medida através da dimensão fractal da vegetação indicou uma maior complexidade estrutural na floresta em relação à pastagem. O trabalho auxiliou no entendimento do funcionamento dos principais sistemas de uso do solo da região do Caparaó Capixaba

Temporary prey storage along swarm columns of army ants: an adaptive strategy for successful raiding?

While pillaging the brood of other ant colonies, Eciton army ants accumulate prey in piles, or caches, along their foraging trails. Widely documented, these structures have historically been considered as by-products of heavy traffic or aborted relocations of the ants' temporary nest, or bivouac. However, we recently observed that caches of the hook-jawed army ant, Eciton hamatum, appeared independently from heavy traffic or bivouac relocations. In addition, the flow of prey through caches varied based on the quantity of prey items workers transported. As this suggested a potential adaptive function, we developed agent-based simulations to compare raids of caching and non-caching virtual army ants. We found that caches increased the amount of prey that relatively low numbers of raiders were able to retrieve. However, this advantage became less conspicuous-and generally disappeared-as the number of raiders increased. Based on these results, we hypothesize that caches maximize the amount of prey that limited amounts of raiders can retrieve, especially as prey colonies coordinately evacuate their brood. In principle, caches also allow workers to safely collect multiple prey items and efficiently transport them to the bivouac. Further field observations are needed to test this and other hypotheses emerging from our study.Nanyang Technological UniversityA CNPq Productivity grant (PQ-2017 grant no. 311790/2017-8) to N.C.; a CAPES PROEX Psicologia Experimental 2016/1964 to N.C., H.P.d.L., R.S.F.-C., R.L.C.d.L. and PROCAD Amazônia; a Presidential Postdoctoral Fellowship (M408080000) from Nanyang Technological University to S.T. CNPq provided H.P.d.L.’s PhD scholarship

ATLANTIC ANTS: a data set of ants in Atlantic Forests of South America

International audienc