ABSTRACT
Parasitizing behavior of Cervellus piranga Penteado-Dias (Hymenoptera, Braconidae, Braconinae) on papaya borer weevil Pseudopiazurus obesus Marshall (Coleoptera, Curculionidae). The papaya borer weevil Pseudopiazurus obesus is a pest associated with papaya crops in Brazil and Cervellus piranga is a naturally-occurring parasitoid which may contribute to regulate populations of this pest. We aimed at describing the parasitizing behavior of the parasitoid C. piranga on papaya borer weevil P. obesus larvae under field conditions. The sequence of events related to the parasitizing behavior of C. piranga is similar to other braconid species and includes the location and recognition of the attacked host plant followed by walks on the host plant and touching it with the tip of the antennae and the ovipositor. In the following event, the parasitoid assesses the suitability of the host by speeding up antennae and ovipositor movements. After locating and accepting the host, the parasitoid remains inactive on oviposition aperture sites and starts moving the antennae. Afterwards, the parasitoid inserts its ovipositor and starts cleaning it repeatedly. The female of C. piranga inserts the ovipositor through the hole and lay one egg into the papaya weevil borer. After oviposition, the female cleans continuously both ovipositor and antennae before leaving to forage for a new host.
Comportamento de parasitismo de Cervellus piranga Penteado-Dias (Hymenoptera, Braconidae, Braconinae) sobre a broca-do-mamoeiro Pseudopiazurus obesus Marshall (Coleoptera, Curculionidae). A broca-do-mamoeiro Pseudopiazurus obesus é uma praga de cultivos de mamão no Brasil e Cervellus piranga é um parasitóide que ocorre naturalmente no campo e pode contribuir para a regulação da população desta praga. O objetivo do presente trabalho foi a descrição do comportamento de parasitismo do parasitoide C. piranga sobre larvas da broca-do-mamoeiro P. obesus em condições de campo. A sequência de eventos relacionados ao parasitismo de C. piranga é similar a outras espécies de braconídeos e inclui a localização e o reconhecimento da planta hospedeira atacada, caminhamento na planta e toque desta com as antenas e o ovipositor. No próximo evento, o parasitoide acessa a adequabilidade do hospedeiro através do aumento dos movimentos da antena e do ovipositor. Após localizar e aceitar o hospedeiro, o parasitoide fica imóvel no sítio de oviposição e inicia a movimentar a antena. Em seguida, o parasitoide insere o ovipositor e o limpa repetidamente. A fêmea de C. piranga insere o ovipositor através da abertura e deposita um ovo na broca-do-mamoeiro. Após a oviposição, a fêmea limpa continuamente o ovipositor e a antena e abandona a planta para um novo forrageamento.
ABSTRACT
Crocidosema aporema (Walsingham) is a major pest of legumes in the southern cone of Latin America. The mating behaviour of two allopatric populations (Uruguay and Brazil) of C. aporema kept in captivity was studied by observing the posture of calling females, the temporal pattern of pheromone emission and mating, and the response of males to calling females in olfactometer tests. Female calling and mating was observed during the scotophase, from the first to the seventh night after adult emergence. Male response was evaluated at night using a single calling female in a Y-shaped olfactometer. Females adopted a characteristic calling posture, extruding the pheromone gland from the tip of the abdomen. Most females started calling during the second scotophase, and all females called from the third, between the fifth and seventh hours after the onset of the scotophase. Most of the couples mated once throughout the experiment, between the third and sixth night and during the middle of the dark phase. Males preferentially chose the female arm in olfactometer tests, considering both the first arm chosen and the number of visits during the observation period. Our results describe for the fi rst time the temporal pattern associated to the reproductive behaviour of C. aporema. We also provide evidence that this tortricid is monoandrous, and that pheromones are used in intersexual communication for mate finding. Our data will be used to optimize the collection of female sex pheromones for chemical characterization in order to develop a monitoring tool for this pest.
Subject(s)
Animals , Female , Male , Lepidoptera/physiology , Sexual Behavior, Animal , Time FactorsABSTRACT
Descrição da larva e pupa da broca do mamoeiro Pseudopiazurus papayanus (Marshall) (Coleoptera, Curculionidae, Piazurini). Larvas, pupas e adultos de Pseudopiazurus papayanus (Marshall, 1922) estão associadas com Carica papaya Linnaeus, 1753 (Caricaceae). A larva de último instar e a pupa são descritas e ilustradas. O dimorfismo sexual observado no ultimo segmento abdominal das pupas, também é ilustrado.
Subject(s)
Animals , Coleoptera/anatomy & histology , Coleoptera/classification , Coleoptera/growth & development , Carica , Larva/growth & development , Pupa/growth & developmentABSTRACT
As respostas de Diabrotica speciosa (Germar) para armadilhas com adultos foram estudadas como sugestão da produção de feromônio. Inicialmente, um ensaio para estabelecer a altura adequada para colocação de armadilhas para capturar D. speciosa foi conduzido em campo de feijão. Armadilhas colocadas a 0,25 m de altura capturaram cerca de 3,5 vezes mais adultos do que a 0,5; 0,75 e 1,0 m. As respostas para fêmeas e machos virgens de duas idades (mais novos = 24 a 72h e mais velhos = 72 a 120h após emergência de adultos), fêmeas e machos copulados foram avaliadas em campo de feijão consorciado com café, Coffea arabica L. Armadilhas com fêmeas virgens capturaram cerca de 22 (mais jovens) e 13 vezes (mais velhas) mais adultos machos do que as testemunhas (armadilhas sem insetos). Capturas foram cerca de 70 por cento mais efetivas usando fêmeas mais jovens. Nenhum dos outros tratamentos aumentou as capturas nas armadilhas. Os resultados indicam que há um feromônio sexual produzido por fêmeas em D. speciosa.
The field responses of Diabrotica speciosa (Germar) to traps baited with adults were studied as an suggestion of the pheromone production. Firstly, an assay to settle a suitable height placement to capture D. speciosa was carried out in common beans, Phaseolus vulgaris L., field. Traps placed at 0.25-m height captured ca. 3.5 times more beetles than 0.5, 0.75 and 1.0-m traps. The responses to virgin females and males of two ages (younger = 24 to 72h and older = 72 to 120h after adult emergence), mated females and males were assessed in common bean interplanted among coffee, Coffea arabica L., field. Virgin females baited traps captured ca. 22 times (younger) and 13 times (older females) more male beetles than control traps. Captures were ca. 70 percent more effective using younger females. None of the other treatments improved trap attraction. These results strongly indicated that there is a female-produced sexual pheromone in D. speciosa.