Effect of energetic cost to maintain the trap for Myrmeleon brasiliensis (Neuroptera, Myrmeleontidae) in its development and adult size

Abstract

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...

Influence of the microhabitat on the trap construction of Myrmeleon brasiliensis (Neuroptera: Myrmeleontidae) larvae

“…Thus, being in an environment that causes less destruction to the traps can diminish energy expenditure. Moreover, development time is longer for larvae that do not forage (Lima & Silva, 2017).Therefore, the lifecycle of the larvae on the trail could be longer than that among the larvae on the slope of the cliff, which implies that larvae on the slope of the hill can become more abundant in the environment in a given moment due to natural selection. For example, in years with more rainfall, larvae in the protected microhabitat can maintain the emergence rate of adults and the laying of eggs, whereas those in the exposed environment may remain in the larval phase for a longer period of time, thereby contributing less to the population size in the area.…”

“…In the natural environment, factors such as wind, falling vegetal matter, rainfall, and the transit of other animals can destroy the traps of antlion larvae (Gotelli, 1993). The construction and maintenance of a trap requires the expenditure of energy (Burgess, 2009;Lima & Silva, 2017) and larvae whose traps have been disturbed have a 50% lower growth rate compared to those whose traps have not been disturbed (Griffiths, 1980).…”

Effect of asymmetric competition on distance among <i>Myrmeleon brasiliensis</i> (Návas, 1914) (Neuroptera: Myrmeleontidae) larvae

“…Larvae that remain in groups are subject to competition for prey items, the destruction of their traps by neighboring larvae and cannibalism (Gotelli, 1993;Day & Zalucki, 2000;Lima, 2016). Isolated larvae avoid these problems, but at the cost of moving to a different location and reconstructing the trap (Lucas 1985;Lima & Silva, 2017). Thus, there must be a competitive advantage for larger larvae to forage farther from other M. brasiliensis larvae.…”

Effect of rain on trap building by Myrmeleon brasiliensis in a riparian woodland from the Cerrado biome in Brazil

“…As the rebuilding of destroyed antlion traps requires high energy expenditure of the larvae (Griffiths, 1980;Lima & Silva, 2017), it was hypothesized that individuals of M. brasiliensis do not build traps in the rainy season and only rebuild their traps when the soil dries out. The riparian forest studied in the present investigation has two well-defined seasons: a rainy season from November to April and a dry season from May to October.…”