Seasonality of insects in the semi-arid Caatinga of northeastern Brazil

Abstract

ABSTRACT. Seasonality of insects in the semi-arid Caatinga of northeastern Brazil. Insects are essential to tropical ecosystems functioning. In semi-arid regions, the increase in abundance and/or activity (e.g. reproduction and foraging behavior) of insects is usually associated with climatic variables. The present study investigates which climatic variables are best predictors of insect abundance in an area of Caatinga in northeastern Brazil. Individuals were sampled for 24 months using Malaise and pitfall traps, and beating trays. A total of 58925 individuals belonging to 20 insect orders were collected. The most abundant orders were Hymenoptera, Diptera, Collembola and Coleoptera. Most orders studied showed a clear maximum abundance in the rainy season. Rainfall and humidity were the best predictors of insect abundance in the Caatinga. However, no climatic variable could explain Psocoptera and Blattodea variance in abundance/activity. Our results suggest that climatic changes associated with rainfall patterns in the Caatinga may affect ecosystem processes and services that depend direct or indirectly on insect abundance/activity. KEYWORDS. Abundance; climatic variables; insect availability; Neotropical region. RESUMO. Sazonalidade de insetos na Caatinga do Nordeste Brasileiro. Os insetos são abundantes e essenciais para o funcionamento dos ecossistemas terrestres tropicais. No entanto, a abundância e/ou atividade (e.g. reprodução ou forrageio) destes organismos podem ser fortemente influenciadas pelas variáveis climáticas. Este estudo examina quais as variáveis climáticas podem atuar como preditoras da abundância e/ou atividade dos insetos em uma área de Caatinga do Nordeste brasileiro. Ao longo de 24 meses, os insetos foram coletados mensalmente utilizando armadilhas Malaise, armadilhas tipo "pitfall" e guarda-chuva entomológico. Um total de 58925 indivíduos de 20 ordens foi coletado. As ordens mais abundantes foram Hymenoptera, Diptera, Collembola e Coleoptera. Entre as doze ordens mais abundantes, dez apresentaram os seus maiores picos durante a estação chuvosa. A precipitação e a umidade relativa foram os principais preditores dos padrões de abundância e/ou atividade dos insetos na caatinga. Nenhuma variável climática foi relacionada com o número de indivíduos coletados de Psocoptera e Blattodea. Os efeitos das variáveis climáticas sobre os insetos sugerem que alterações no clima da caatinga, especialmente em seu padrão de precipitação, podem afetar os serviços ecossistêmicos que dependem direta e indiretamente da abundância e/ou atividade destes organismos.PALAVRAS-CHAVE. Abundância; disponibilidade de insetos; região Neotropical; variáveis climáticas.

Beetles (Insecta, Coleoptera) associated with pig carcasses exposed in a Caatinga area, Northeastern Brazil

“…The vegetation varies from open to dense arboreal Caatinga, with a strong deciduous characteristic during the dry season. The soil is sandy and arid and the topography is irregular, with inselbergs and rocky outcrops (Vasconcellos et al, 2010).…”

“…The main objective was to analyse the diversity of the Coleoptera fauna associated with pig (Sus scrofa Linnaeus, 1758) carcasses, during the dry and wet seasons in Caatinga, a dry forest endemic to Brazil, whose insect fauna is poorly known (Vasconcellos et al, 2010;Creão-Duarte et al 2013;Alves et al, 2014). Brief comments on the main families of forensic importance are also included, highlighting the richness, abundance, behaviour and ecological aspects of some species.…”

Temporal Variation of Membracidae (Hemiptera: Auchenorrhyncha) Composition in Areas of Caatinga with Different Vegetation Structures

“…During the rainy season there is a substantial increase in plant biomass that provides resources for many different groups of insects such as the Hemiptera-Auchenorrhyncha, which become abundant under these conditions (Vasconcellos et al, 2010).…”

Soil-sampled Termites in Two Contrasting Ecosystems within the Semiarid Domain in Northeastern Brazil: Abundance, Biomass, and Seasonal Influences

“…The abundances and biomasses of termites at the dry tropical forests site did not demonstrate significant variations between the dry and rainy seasons. Other studies undertaken in seasonally dry tropical forests in the region, however, demonstrate an effect on vertical distribution, foraging and abundance of insects in general (Moura et al, 2006;Araújo et al, 2010;Vasconcellos et al, 2010a), including termites (Melo & Bandeira, 2004;Vasconcellos et al, 2010b). Apparently, other characteristics, such as food availability, soil moisture, and interspecific interactions, could minimize climatic effects on soil fauna in seasonally dry tropical forest ecosystems.…”