Abstract Parasitoids manipulate the host metabolism for their own benefit by influencing its development and the direct or indirect result of it is the host death. This study aimed to observe the influence of parasitoidism of Paravilla sp. (Diptera, Bombyliidae) on the development of antlion larvae Myrmeleon brasiliensis (Návas, 1914) (Neuroptera, Myrmeleontidae). The specific objectives were to verify in which larval instars the parasitoid oviposition occurs, the influence of the parasitoid on the larval and pupal development time of M. brasiliensis, the differences in body length of the antlion larvae, as well as of the sex ratio of M. brasiliensis adults. For this, the larvae were differentiated in 1st, 2nd and 3rd instar and measures on body length (head-abdomen) and accompanied until the emergence of the adult. It was observed that the parasitoid Paravilla sp. attacked only the 2nd and 3rd instar larvae. The parasitoid Paravilla sp. oviposited only in 2nd and 3rd instars larvae. No significant differences were observed on larval development time, in the larval body length and in the adult sex ratio between groups of parasitized and non-parasitized M. brasiliensis larvae, however, was observed differences in the pupal development time of these two groups. Thus, we can conclude that the parasitoid Paravilla sp. influences the development time of M. brasiliensis pupal.

Las larvas de Myrmeleon brasiliensis son depredadoras que utilizan la estrategia de forrajeo de tipo "sit-and-wait" para capturar a sus presas y así construyen trampas en forma de embudo en el suelo arenoso y permanecen enterradas esperando que caigan las presas. El objetivo de este trabajo fue observar el comportamiento de depredación de las larvas de M. brasiliensis en los tres instares larvales, para eso, se recolectaron hormigas cortadoras y se ofrecieron manualmente como presas a 14 larvas de 1° instar y 33 de 2° y 3° instar. Se contó el número de ataques del depredador a la presa, el número de escapes de la presa y el éxito de captura de presas de cada larva de M. brasiliensis. Las larvas de M. brasiliensis de 1° instar atacaron más a sus presas, seguidas por las larvas de segundo y tercer instar. En cuanto al número de escapes de las presas, no se observó diferencia signifcativa para ese comportamiento entre las larvas. En relación al éxito en la captura de las presas, las larvas de 3° instar presentaron más éxito, con una tasa de depredación de 96, 96%, seguida por las larvas de 2° (69,70%) y 1° instar (14,28%).

Myrmeleon brasiliensis larvae are predators that use the sit-and-wait tactic to catch their prey, and to fulfll this pitmaking funnel traps in the sandy soil and remain buried waiting for prey to slip. The objective of this study was to observe the predation behavior of larvae of M. brasiliensis in the three larval instars, for this leaf cut ant were collected manually and offered within the plastic pots as prey for 14 larvae of 1st instar larvae, 33 of 2nd and 3rd instar. It was counted the number of attacks of the predator to prey, the number of escapes from jail and the success of prey capture for each larva of M. brasiliensis. The larvae of M. brasiliensis 1st instar attacked more times its prey, followed by larvae of 2nd and 3rd instar. On the number of escape of prey, there was no signifcant difference in this behavior among larvae. Regarding the success in capturing prey, the larvae of 3rd instar were more successful, with a predation rate of 96.96%, followed by the larvae of 2nd (69.70%) and 1st instar (14.28 %).