Aspectos bioecológicos de uma espécie de Fulcidacini (Coleoptera: Chrysomelidae: Cryptocephalinae)

Abstract

Cryptocephalinae (Insecta: Coleoptera: Chrysomelidae) are morphologically characterized by the prognathous head, flattened in the anterior part and retracted to the prothorax; and also in relation to its biology by the peculiarity in building fecal cases used as shelters by both females, to protect each egg layed, as well by the larvae, from hatching to before pupation. This group is little known taxonomically and bioecologically. In this scenario, this study proposes to describe (1) the use of time throughout development; as well as (2) reproductive indicators, of a species of Fulcidacini (Cryptocephalinae). Breeding started from couples of insects obtained by active collection, aiming to obtain eggs for the life cycle study. Larvae that hatched and managed to break the “fecal capsule” (n = 51) were individualized in containers and fed on the host plant (Malvaceae). The dates were recorded for the following biological phenomena: oviposition; rupture of the fecal capsule; time limits of paralysing behavior between each step of the “molting larval processes”; adult exit; and death. Reproductive performance was determined from couples formed from the adults specimens which left the fecal cases. All eggs produced were transferred to microtubes in order to check viability. Exsiccates were prepared to identify the food plant, wich was deposited in herbarium. The plant was identified as Waltheria indica L. (Malvaceae) and the insect as Pseudochlamys sp. (Fulcidacini). Given the difficulty in determining the dates of the ecdisis that occur inside the protective case, the instars were established using the following criteria: partial sealing of the case; paralization behavior; and resumption of food activity. Thus, the durations (mean ± standard deviation, in days) of the periods were as follows: 15.27 ± 1.45, for the period in the fecal capsule; for the first three larval instars, 10.76 ± 2.26; 9.18 ± 6.25; 10.62 ± 6.07; and 16.27 ± 7.51 for the active phase of the fourth instar. The period of inactivity (prepupa ± pupa) was 28 ± 2.48. Overall longevity was 63.87 ± 15.67 days. The females longevity was 71.25 ± 13.64 days. Pre-oviposition period of 21 ± 4.08; oviposition 41 ± 16.38; and post-oviposition, 5.5 ± 1.2 days. The total number of eggs layed per female (fecundity) was 47.25 ± 29.76 (ranging from 17 to 78); with an average viability of 42.3%. The results confirm W. indica as food plant for Pseudochlamys sp. (Cryptocephalinae: Fulcidacini). This study presents the first information on reproductive performance for this Chrysomelidae subfamily.