Desenvolvimento pré-imaginal de uma espécie de Agroiconota (Spaeth. 1913) (Coleoptera, Chrysomelidae, Cassidinae) alimentando-se de Ipomoea pescaprae (L.) R. Br. (Convolvulaceae), no Estado de Alagoas

Abstract

Preimaginal development of a species of Agroiconota (Spaeth. 1913) (Coleoptera, Chrysomelidae, Cassidinae) feeding on Ipomoea pes-caprae (L.) R.Br. (Convolvulaceae), in the State of Alagoas. The Chrysomelidae family is one of the most abundant of the Coleoptera order, which includes 12 subfamilies, with emphasis on Cassidinae, the second in terms of diversity. In this subfamily, few studies are referring to biological aspects both in general and about species from the State of Alagoas, a situation that justifies the development of research related to the knowledge of bioecological aspects of representatives of this group. Therefore, the objective of this work is to describe the pre-imaginal development (egg to adult) of a species of Cassidinae in Convolvulaceae. The study was carried out at the Laboratory of Bioecology of Insects (LABIN) of the Institute of Biological and Health Sciences, based on the creation of support initiated with two adults collected at Campus A. C. Simões, of the Federal University of Alagoas, in the municipality of Maceió (10º26 '36"S 36º13'27" W). In the field, the adults were very close together, on the abaxial surface of the leaf on which they fed. The sexing was carried out from the matings in the laboratory, rearing container, with a daily exchange of food (leaves of the food plant). The dates of the following biological events were recorded: oviposition, larval hatching, larval and pupal ecdysis, adult emergence, and deaths over the observation period. The calculation of the duration data was carried out to determine the number and duration of the larval and pupal instars, as well as aspects of the behavior of the immature forms. The insects were confirmed as belonging to the genus Agroiconota Spaeth, 1913; and the food plant, Ipomoea pes-caprae (L.) R. Br. The eggs were laid in different places in the container: on the leaf, on the paper towel, at the base of the cage as well as on the inner surface of the dome. Of the 119 eggs obtained, 78 hatched as larvae. The embryonic period lasted on average (± standard deviation, in days) 8.84 ± 0.56 days; the first larval instar (L1) 4.87 ± 1.3; L2 3.19 ± 0.58; L3 3.05 ± 0.39; L4 3.53 ± 0.78; L5 with feeding activity, lasted 5.81 ± 0.85, as prepupa 2.36 ± 0.55, and total L5 7.40 ± 2.13 days. The larvae, in general, presented a light yellow coloration; in the larval instars, the protective strategy formed by a tegumentary furcation in the dorsal part of the end of the abdomen was observed to sequentially retain the exuviae, together with part of the feces produced. The duration of the total larval period was 22.83 ± 1.63 days, and the active larval period was 20.46 ± 1.48 days. The pupal period lasted 7 ± 0.32 days and in this phase, the pupae showed a brownish color with stronger yellow tones. The period of feeding inactivity (prepupa + pupa) was 9.36 ± 0.52 days. The post-embryonic period lasted 29.83 ± 1.62 days and the pre-imaginal (embryonic + post-embryonic) 38.67 ± 1.55 days. This study brings the first record of information about the pre-imaginal development of a species of Agroiconota from Northeast Brazil.