Antennal sensilla in Cyclocephala literata Burmeister, 1847 (Coleoptera: Scarabaeidae: Dynastinae) / Sensilas antenais em Cyclocephala literata Burmeister, 1847 (Coleoptera: Scarabaeidae: Dynastinae)

Abstract: Adults of the beetle Cyclocephala literata Burmeister, 1847 are important pollinators to some Magnoliaceae. Is known that insects could find host plants by detecting volatiles through antennal sensilla. Cyclocephala has its three distal antennomeres lamellate, and the surface of each lamella has sensilla trichodea, chaetica, placodea, coeloconica, basiconica and ampullacea. Three kinds of sensilla placodea were found (type I, II and III), and two kinds of sensilla coeloconica were observed (type I and II). Females have on average 10,776 sensilla, of which 10,214 are sensilla placodea, 536 are sensilla coeloconica, and 26 are sensilla basiconica. Males have on average 10,386 sensilla, of which 9,873 are sensilla placodea, 464 are sensilla coeloconica, and 49 are sensilla basiconica. Males and females have similar quantities of sensilla, and sensilla placodea are predominant. The differences observed in the number of sensilla of males and females were found in other beetles and were attributed to the detection of cospecific sexual pheromones by one of the sexes, or to the detection of plant volatiles. The antennal sensilla of C. literata is described and quantified in present study, and some perspectives about the differences kind of chemical communication, pollination, and antennae dimorphism is discussed.

Resumo: Adultos do besouro Cyclocephala literata Burmeister, 1847 desempenham importantes funções de polinização em plantas da família Magnoliaceae. É conhecido que muitos insetos encontram plantas hospedeiras pela detecção de voláteis pelas sensilas antenais. Cyclocephala possui os três antenômeros distais lamelados e na superfície de cada lamela possuem sensila trichodea, caética, placódea, coelocônica, basicônica e ampulacea. Foram encontrados três tipos de sensilas placódeas (tipo I, II e III), e dois tipos de sensilas coelocônicas (tipo I e II). Fêmeas apresentam em média 10.776 sensilas, das quais 10.214 são sensilas placódeas, 536 são sensilas coelocônicas e 26 são sensilas basicônicas. Os machos apresentaram em média 10.386 sensilas, das quais 9.873 são sensilas placódeas, 464 são sensilas coelocônicas e 49 são sensilas basicônicas. Machos e fêmeas apresentam quantidades semelhantes de sensilas e as sensilas placódeas são predominantes. As diferenças encontradas nas quantidades de sensilas em machos e fêmeas também foram encontradas em outros besouros e foram atribuídas a detecção de feromônios coespecíficos por um dos sexos, ou para detecção de voláteis de plantas. A sensila antenal de C. literata é descrita e quantificada no presente estudo, e algumas perspectivas sobre as diferenças entre os tipos de comunicação química, polinização e dimorfismo antenal é discutido.

Morphology of the antennal sensilla of two species of Hoplopyga Thomson, 1880 (Coleoptera, Scarabaeidae, Cetoniinae)

ABSTRACT Antennal sensilla are important functional elements of sensory systems in insects. This study aimed to determine the morphology and structure of the sensilla of two species of the genus Hoplopyga. Adults of Hoplopyga liturata (Olivier, 1789) were collected in traps with sugarcane juice as an attractant. Thereafter, larvae of Hoplopyga albiventris (Gory and Percheron, 1833) were collected in mounds of termites (Cornitermes cumulans (Kollar, 1832) Isoptera). Then, they were reared in the laboratory for adult observations. Antennae of H. liturata and H. albiventris have sensilla chaetica, trichodea, placodea (type I and II), coeloconica (type I and II), and ampullacea (or pore). Females of H. liturata have a total of about 10657 sensilla and males have about 12512, whereas females of H. albiventris have about 16490 sensilla and the males 24565 sensilla. Sensilla placodea are predominant in the antenna of males and females of both species.