Antlion larvae Myrmeleon brasiliensis Návas, 1914 (Neuroptera, Myrmeleontidae) are sit-and-wait predators who build traps to catch their prey. The aim of this study was to observe under laboratory conditions, how the energy cost spent on maintenance of their traps affects: the larval developmental time, time spent as a pupa, mortality rate of larvae and adult size. M. brasiliensis larvae were collected in the municipality of Aquidauana, Mato Grosso do Sul, Brazil and were individually maintained in plastic containers and subjected to two treatments. In the control treatment larvae did not have their traps disturbed while in the manipulated treatment, larvae had their traps disturbed three times a week. The experiments were followed until adult emergence. When the adults emerged, their body size (head-abdomen), anterior and posterior wing span and width were measured. Furthermore, the number of larvae that died during the experiment was recorded. The results showed that the larvae whose traps were manipulated had longer larval development time, smaller pupal development time and were smaller adults. It can be concluded that the energy expenditure spent on maintenance of the trap constructed by M. brasiliensis larvae can affect the development of negative ways, represented by a longer larval development and reduced adult size.Keywords: ant-lion larvae, body size, sit-and-wait predators.Efeito do custo energético com a manutenção da armadilha de Myrmeleon brasiliensis (Neuroptera, Myrmeleontidae) no seu desenvolvimento e no tamanho dos adultos ResumoEfeito do custo energético com a manutenção da armadilha de Myrmeleon brasiliensis no seu desenvolvimento e no tamanho dos adultos. Larvas de formiga-leão Myrmeleon brasiliensis são predadores senta-espera que constroem armadilhas para a captura de suas presas. O objetivo deste trabalho foi observar em laboratório, como o gasto energético despendido com a manutenção dessas armadilhas afeta: o tempo de desenvolvimento larval, o tempo de pupa, a taxa de mortalidade das larvas e o tamanho dos adultos. M. brasilienses foram coletadas no município de Aquidauana, Mato Grosso do Sul, então foram individualizadas em potes plásticos e submetidas a dois tratamentos. No tratamento controle, as larvas não tiveram suas armadilhas perturbadas e no tratamento manipulado, as larvas tiveram as suas armadilhas perturbadas três vezes por semana. Os experimentos foram acompanhados até a emergência dos adultos. Quando esses emergiam, era medido o seu tamanho corporal (cabeça-abdômen), envergadura da asa anterior e posterior e largura da asa anterior e posterior. Além disso, foi contabilizado o número de larvas mortas no decorrer dos experimentos. Como resultado foi observado que as larvas manipuladas apresentaram o tempo de desenvolvimento larval maior, o tempo de pupa menor e o tamanho dos adultos foi menor. Pode-se concluir que o gasto energético despendido com a manutenção da armadilha construída pelas larvas M. brasiliensis pode afetar o seu desenvolvimento de maneiras negativa...

Seasonality in the Cerrado biome of Brazil is characterized by a dry season and a rainy season, affecting the availability of water and generating nutritional limitations. Thus, plants and animals have developed adaptive mechanisms in order to survive in this environment. Insects known as antlions (Neuroptera: Myrmeleontidae) occur in areas of the Cerrado and build traps in dry soil to capture prey items. In the rainy season, these insects are unable to forage due to the waterlogged soil. The aim of this study was to investigate the influence of the rainfall regime in the Cerrado on aspects of trap-building behavior, larval development and morphological characteristics of adult antlions. Larvae of the antlion Myrmeleon brasiliensis (Návas, 1914) were observed and collected in an area of the Cerrado biome in the municipality of Aquidauana (MS), Brazil. Observations were performed in the rainy and dry seasons to determine the abundance of traps built by M. brasiliensis larvae. In the laboratory, experiments were performed involving the manipulation of the frequency of simulated rain on the traps. The results revealed that variations in rainfall due to seasonality in the Cerrado affect M. brasiliensis larvae, with greater foraging observed in the dry season. The laboratory experiments demonstrated that differences in the frequency of rains affect the mortality of the larvae, larval development time and the size of the adults. Thus, variations in rainfall patterns can lead to variations in the characteristics of the population structure of M. brasiliensis in areas of the Cerrado biome in Brazil.

Antlion larvae of Myrmeleon brasiliensis (Návas, 1914) build their traps in a microenvironment with protection from the direct action of rain and other perturbations as well as microhabitats that are less protected from disturbances that can destroy the traps. Differences in microhabitats may affect the characteristics of the trap-building process due the high energy expenditure exerted in building and maintaining these traps, which led to the following question: Do antlion larvae of M. brasiliensis build larger traps in protected microhabitats? Considering the occurrence of M. brasiliensis larvae in two microhabitats and the measurements of the size of the larvae and their traps, the hypothesis was that larvae would occur in greater abundance and the trap size would be larger in more protected microhabitats. The results showed that antlions occurred in equal abundance in both microhabitats, but density was greater in the protected microhabitat. Even in months with more rainfall, M. brasiliensis larvae continued to forage throughout the year in the protected microhabitat and the investment in trap size was greater in this microhabitat. This suggests that the larvae of the protected microhabitat have an advantage, given that they have the possibility of foraging throughout the year.