Ciclo de vida y enemigos naturales de Mechanitis menapis (Lepidoptera: Ithomiini)

Las mariposas de la tribu Ithomiini son uno de los modelos biológicos más estudiados en años recientes en trabajos de biogeografía, taxonomía y evolución. Sin embargo, aun cuando la biología y distribución de sus especies es mejor conocida que la de otros grupos de mariposas, existen aspectos de la historia natural poco estudiados que permitirían un mejor entendimiento del comportamiento de sus poblaciones y las interacciones con su ambiente. En este trabajo, se estudió la historia natural de la mariposa, Mechanitis menapis mantineus Hewitson (Nymphalidae: Ithomiini) y sus enemigos naturales en el oeste de Ecuador. Para ello, se realizó la identificación de las plantas hospederas, se estudió el ciclo de vida y los factores de mortalidad de los estados inmaduros. Adicionalmente, se identificaron los parasitoides asociados a la especie en la zona de estudio. Se identificaron tres plantas hospederas, las cuales son nuevos registros para la especie en la región. Asimismo, se describió la morfología de los estados inmaduros y su tiempo de desarrollo. Finalmente, se identificaron los principales enemigos naturales y se describieron aspectos de la historia natural y comportamiento de Hyposoter sp. (Ichneumonidae: Campopleginae), principal parasitoide de larvas. Los resultados de este trabajo, proporcionan información esencial para la revisión taxonómica del género Mechanitis F. y para continuar el estudio de la interacción de esta especie con sus plantas hospederas y enemigos naturales.

Life cycle and natural enemies of Mechanitis menapis (Lepidoptera: Ithomiini). The butterflies of the Ithomiini tribe are one of the most-studied biological models of recent years in terms of biogeography, taxonomy, and evolution. However, even though their biology and distribution is better known than many other groups of butterflies, there are unknown aspects of their natural history that would improve our understanding of their behavior, population dynamics, and interactions with their environment. In this work, we studied the natural history of the butterfly Mechanitis menapis mantineus Hewitson (Nymphalidae: Ithomiini), and its natural enemies, in Western Ecuador. We identified three host plants, which are new records for the species in this region. We documented the life cycle and described the morphology of the immature stages, their development time, and studied the factors associated with mortality of these immature stages. Additionally, we identified the parasitoids associated with the species in the study area. In particular, we documented aspects of the natural history and behavior of Hyposoter sp. (Ichneumonidae: Campopleginae), the main parasitoid of the larvae. The results of this work provide essential information for the taxonomic revision of the genus Mechanitis F. as well as the continued study of the interactions between the butterfly, its host plants, and natural enemies.

Patrones comportamentales de fóridos (Diptera: Phoridae) parasitoides de Atta colombica (Hymenoptera: Formicidae) / Behavioral patterns of parasitoid phorids (Diptera: Phoridae) of Atta colombica (Hymenoptera: Formicidae)

ResumenEl éxito de las interacciones parasitoide-hospedero está determinado por la conducta de búsqueda, reconocimiento, ataque y defensa que despliegan los participantes en dicha interacción. Para comprender los patrones comportamentales entre los fóridos parasitoides y su hospedero, Atta colombica, se realizaron observaciones en un fragmento de bosque en el departamento de Córdoba, con un esfuerzo muestral de 186 horas en tres nidos de esta. Se recolectaron fóridos, hormigas atacadas y la carga que llevaban. En total se capturaron 52 individuos de Eibesfeldtphora attae y 54 de Apocephalus colombicus. Se observaron diferencias en cuanto a la forma de ataque y el microhábitat preferido por los parasitoides. No hubo preferencia aparente por el tamaño de las hormigas que atacaron los fóridos, pero seleccionaron cargas de mayor tamaño para posarse sobre ellas. Cuando las hormigas respondieron al ataque, emplearon defensas individuales (adoptando posiciones o aumentando su velocidad) o grupales (cuando hormigas vecinas atacaban al parasitoide). Los fóridos parasitoides especializan su conducta con el fin de garantizar un ataque exitoso sobre su hospedero, quien responde modificando su comportamiento según el parasitoide atacante.

AbstractIn ecology, the success of parasitoid-host interactions is determined by the behavior of seeking, recognition, attack and defense deployed by the participants in the interaction. Our study aimed to understand the behavioral patterns between parasitoid phorids and their host Atta colombica from a forest fragment of Córdoba department, Colombia. We observed three nests of Atta colombica, from December 2013 to Januray 2015 (including dry and rainy seasons), for a total effort of 189 hours. We observed Phorids, their attacks to ants and collected their loads; we also considered differences in the way the parasitoids attacked and observed the microhabitat they preferred. A total of 52 individuals of Eibesfeldtphora attae and 54 of Apocephalus colombicus were collected. Apparently there was no preference for the size of the ants that were attacked by phorids, but larger loads were selected to land on them. When the ants responded to the phorid attack, they used individual defenses (adopting positions or increasing their speed) or grupal defenses (closer ants attacking the phorid). Parasitoid phorids have specialized their behavior, in order to ensure a successful attack on their host, who responded by modifying its behavior, according to the attacker (parasitoid).

First report of Exomalopsis fulvofasciata (Hymenoptera: Anthophoridae) as host of two Timulla species (Hymenoptera: Mutillidae)

Two species of Timulla Ashmead that parasitize nests of Exomalopsis fulvofasciata (Hymenoptera: Apidae) in riparian vegetation in the Miranda Pantanal, Mato Grosso do Sul, Brazil were recorded. Also, the behavior of Timulla species, and first report of T. intermissa in the Brazilian Pantanal was reported.

Registramos duas espécies de Timulla Ashmead parasitando ninhos de Exomalopsis fulvofasciata (Hymenoptera: Apidae) em mata ciliar na região do Pantanal de Miranda, Mato Grosso do Sul, Brasil. Foram observados comportamentos das espécies de Timulla e primeiro registro de T. intermissa para o Pantanal Brasileiro.

Mortalidade de larvas e pupas de Chrysomya megacephala (Fabricius) (Diptera: Calliphoridae) e seu parasitismo por microhimenópteros na cidade do Rio de Janeiro, RJ / Mortality of larvae and pupae of Chrysomya megacephala (Fabricius) (Diptera: Calliphoridae) and its parasitism by microhymenopteran in Rio de Janeiro county, RJ, Brazil

Devido à importância de Chrysomya megacephala (Fabricius) como vetor de microrganismos patogênicos em grandes aglomerações humanas, este trabalho teve por objetivo conhecer a mortalidade da mosca durante as fases larval e pupal e o seu parasitismo por microhimenópteros. Larvas de C. megacephala de terceiro ínstar, juntamente com seu substrato de criação (carne bovina moída putrefata), foram colocadas por sete dias próximo a lixeiras, no campus do Instituto Oswaldo Cruz /FIOCRUZ e no Jardim Zoológico do Rio de Janeiro, Rio de Janeiro, RJ, de agosto de 1999 a julho de 2000. As pupas recolhidas após o período em campo foram individualizadas em cápsulas de gelatina e mantidas em câmara climática (27°C) por aproximadamente 35 dias. Foi verificado o número de pupas com emergência de moscas, com emergência de parasitóides e pupas sem emergência, sendo as últimas dissecadas. Obteve-se mortalidade média de 29,6 percent durante a fase larval e pupal das moscas quando expostas ao ambiente externo, contra 16,5 percent do grupo controle. Das pupas trazidas do campo, 5,6 percent estavam parasitadas, de 77,6 percent emergiram moscas e de 16,8 percent não houve emergência. Tachinaephagus zealandicus Ashmead (Encyrtidae) mostrou-se um promissor inimigo natural de C. megacephala, com a maior percentagem de colonização das pupas parasitadas (78,6 percent) e maior número médio de parasitóides por pupa (15,2). Pachycrepoideus vindemiae Rondani (Pteromalidae) e Nasonia vitripennis (Walker) (Pteromalidae), apresentaram menor percentagem de parasitismo que a primeira espécie, tanto no IOC como no Zoológico, parasitando 13,2 percent e 8,2 percent das pupas, ambos com 1,0 e 11,1 parasitóides por pupa, em média, respectivamente.

Due to the importance of Chrysomya megacephala (Fabricius) as a pathogenic microoganism vector in large human agglomerations, the objective of this research was to understand the host-parasite relationship under field conditions. Third instar larvae of the fly and putrefying ground beef, replaced every seven days under the same conditions, were placed close to the litter bins, on the campus of the Institute Oswaldo Cruz/FIOCRUZ and the Rio de Janeiro Zoological Garden, Rio de Janeiro, RJ, from August 1999 to July 2000. The pupae taken to the laboratory were screened (fly emergence or not), individualized in gelatin capsules, and placed in a climatic chamber (27°C) for approximately 35 days. After this period, the number of pupae with and without parasitoid emergence was counted and the pupae without emergence were dissected. A natural mean loss of 29.6 percent of fly larva and pupae was detected when exposed to the external environment compared with 16.5 percent in the control group. An average of 5.6 percent of the pupae brougth from the field were parasitized, 77.6 percent produced flies and 16.8 percent had no emergence. Tachinaephagus zealandicus Ashmead was a promising natural enemy to C. megacephala, with the largest percentage of parasitized pupae (78.6 percent) and greater mean number of parasitoids per pupae (15.2). Pachycrepoideus vindemiae Rondani and Nasonia vitripennis (Walker) presented lower percentage of parasitism than T. zealandicus, both in IOC and in the ZOO, parasitizing 13.2 percent and 8.2 percent of the pupae, with 1.0 and 11.1 parasitoids per pupae, on average, respectively.

Distribution, survivorship and mortality sources in immature stages of the neotropical leaf miner Pachyschelus coeruleipennis Kerremans (Coleoptera: Buprestidae)

Distribution, sources of mortality, and survivorship of immatures was investigated during the reproductive season of the neotropical buprestid leaf miner, Pachyschelus coeruleipennis, that burrows in leaves of Croton floribundus (Euphorbiaceae) in SE, Brazil. Immature distribution was investigated by a random sample of 120 shrubs of C. floribundus growing along forest edges. Marked leaves were followed to recorded sources of mortality and survivorship of immature stages. Females lay their eggs preferentially in the young leaves of the host plant, with mines and pupal cells having been found on the middle part of plants. Densities of eggs, active mines, and pupal cells were, respectively, 25 ± 2, 6 ± 1, and 1 ± 0.3 per 100 leaves. Predators and parasitoids accounted for the majority of losses in the immature P. coeruleipennis population. Mortality was 3 times lower in the egg stage than in the last larval instar. Predation rate was greater than parasitism but the latter increased much more during the development of immatures. Survivorship and sources of mortality were different between early and late season sample of leaf-miner immatures. Parasitism rate was greater in the late-season whereas predation was greater in early-season samples. These results are compared with mortality patterns described for other buprestid leaf miners in temperate and tropical regions.

A distribuição, as fontes de mortalidade e a sobrevivência de estágios imaturos do minador de folhas Pachyschelus coeruleipennis (Coleoptera: Buprestidae) foram investigadas em uma floresta semidecídua do Sudeste brasileiro. A distribuição dos imaturos foi avaliada em uma amostra aleatória de 120 plantas jovens de Croton floribundus (Euphorbiaceae) às margens da floresta. Folhas com estágios imaturos do minador foram marcadas e observadas periodicamente para o registro da sobrevivência e das causas de morte. Fêmeas de P. coeruleipennis ovipositam preferencialmente em folhas da porção superior de plantas jovens, sendo que as minas com larvas e as células pupais são encontradas nas folhas da porção média. As densidades de ovos, as minas ativas e as células pupais foram, respectivamente, de 25 ± 2, 6 ± 1 and 1 ± 0,3 por 100 folhas. Predadores e parasitóides foram responsáveis pela maior porcentagem entre os fatores identificados de causas mortis. A taxa de predação foi superior à de parasitoidismo, mas esta última apresentou aumento mais acentuado durante o desenvolvimento dos imaturos. O padrão de sobrevivência e a composição nas causas mortis foram diferentes entre a amostra para o começo e para o final da estação reprodutiva. O parasitoidismo foi maior no final da estação, enquanto a predação o foi no início da estação. Os resultados deste trabalho são comparados com os padrões descritos para outros buprestídeos minadores de folha em regiões temperadas e tropicais.