Sérgio Roberto Rodrigues

The Coleopterists Bulletin publishes a wide variety of articles, notes, and book reviews regarding the biology, taxonomy and ecology of beetles (Coleoptera).

This study describes the antennal ultrastructure in Cyclocephala forsteri Endrodi, 1963, Cyclocephala melanocephala (Fabricius, 1775) and Cyclocephala tucumana Brethes, 1904 (Coleoptera: Scarabaeidae). Adult of Cyclocephala Dejean, 1821 specimens were collected using a light trap placed near a pasture area, segregated by gender, based on male-specific dilated pre-tarsomeres and preserved in 70% alcohol. Scanning electron microscopy (SEM) images of the antenna lamellae were obtained from ten specimens at Universidade Estadual Paulista (UNESP) in Ilha Solteira, SP, Brazil. We identified trichoid, chaetic, placoid, coeloconic, basiconic sensilla, and pores in antenna of all the species. Placoid sensilla were prevalent in the antennal lamellae. The antennae of C. forsteri females had 5,457 sensilla, of which 5,327 (97.62%) were placoid, 123 (2.25%) coeloconic, and seven (0.13%) basiconic, while the antennae of males showed 5,351 sensilla, with 5,238 (97.89%) being placoid, 100 (1.87%) coeloconic, and 13 (0.24%) basiconic. The antennae of C. melanocephala females presented 6,814 sensilla, with 6,581 (96.58%) being placoid, 231 (3.39%) coeloconic, and two (0.03%) basiconic; while those of males had 6,333 sensilla, with 6,023 (95.11%) being placoid and 310 (4.89%) coeloconic. Finally, the antennae of C. tucumana females had 1,981 sensilla, with 1,845 (93.13%) being placoid, 127 (6.42%) coeloconic, and nine (0.45%) basiconic; while the antennae of males had 3,756 sensilla, with 3,656 (97.34%) being placoid, 99 (2.64%) coeloconic, and one (0.02%) basiconic. Overall, adults of C. melanocephala and C. tucumana presented dimorphism in the antennal sensilla.

The objective of this study is to record the injury of Anomala testaceipennis Blanchard, 1851 (Coleoptera: Scarabaeidae: Rutelinae) adults in coffee Coffea arabica L. in municipality of Piumhi, Minas Gerais, Brazil. This is the first reported of the A. testaceipennis attacking coffee.

This study was conducted at the Universidade Estadual de Mato Grosso do Sul, Cassilândia, Brazil from September 2017 to December 2021 in a Brazilian Cerrado. Adults of Anomala testaceipennis Blanchard were collected associated with host plants and taken to the laboratory for studies. Some phytophagous scarab beetles found host plants through detection of plant volatiles. The detection of those odorants is intermediated by antennal sensilla. The main goals of the present study are to describe the antennal sensilla of A. testaceipennis and check the host plants used as food resource. This specie was found feeding on flowers of: Anadenanthera colubrina var. cebil (Fabaceae), Azadirachta indica (Meliaceae), Buchenavia sp. (Combretaceae), Cordia glabrata (Boraginaceae), Inga edulis (Fabaceae), Moquilea tomentosa (Chrysobalanaceae), Paubrasilia echinata (Fabaceae), Tabernaemontana catharinensis (Apocynaceae), Tapirira guianensis (Anacardiaceae), Xylophragma pratense (Bignoniaceae). To the sensilla study, antennae were dissected and images of the sensilla were obtained using a scanning electron microscope. Antennae of A. testaceipennis have sensilla chaetica, trichodea, placodea (type I, II, and III), coeloconica (type I and II), basiconica (type I), and ampullacea (or pore). Males have a total of about 6,243 sensilla of which 5,868 (93.99%) are sensilla placodea, 370 (5.93%) are sensilla coeloconica, and 5 (0.08%) are sensilla basiconica. Females have a total of about 5,119 sensilla of which 4,820 (94.16%) are sensilla placodea, 270 (5.27%) are sensilla coeloconica, and 29 (0.57%) are sensilla basiconica.

Cyclocephaline beetles are flower visitors attracted primarily by major floral volatiles. Addressing the identity of these volatile compounds is pivotal for understanding the evolution of plant-beetle interactions. We report the identification and field testing of the attractant volatiles from trumpet flowers, Brugmansia suaveolens (Willd.) Sweet (Solanaceae), for the beetle Cyclocephala paraguayensis Arrow (Melolonthidae: Dynastinae). Analysis of headspace floral volatiles revealed 19 compounds, from which eucalyptol (57%), methyl benzoate (16%), and β-myrcene (6%) were present in the largest amounts, whereas E-nerolidol in much lesser amounts (1.8%). During a first-field assay, traps baited with Mebe alone or blended with the other two major compounds attracted more beetles than myrcene and eucalyptol alone, which did not differ from the negative controls. In a second assay, Mebe and nerolidol attracted more beetles as a blend than individually. Nerolidol was more attractive than Mebe, and all treatments attracted more beetles than negative controls. The number of attracted beetles in the Mebe-nerolidol blend was greater than the combined sum of beetles attracted to these compounds alone, suggesting a synergistic interaction. The attraction of C. paraguayensis by trumpet-flower volatiles supports the beetle’s extended preference for sphingophilous plants, especially when cantharophilous (beetle-pollinated) flowers are lacking. This phenomenon, thus, might have contributed to the widespread occurrence of this beetle throughout the Brazilian biomes.

Larvae of Leucothyreus spp. have been reported causing damage to several crops in Brazil. From May 2012 to April 2013, adults and immatures of Leucothyreus alvarengai Frey (Coleoptera: Melolonthidae: Rutelinae) samples were obtained from sugarcane (Saccharum officinarum L.) (Poaceae) fields in the municipalities of Naviraí and Nova Andradina, Mato Grosso do Sul, Brazil. Adults were collected with the aid of light traps, whereas immatures were sampled by opening two trench sizes (30 x 30 x 30 cm and 80 x 50 x 40 cm) in the soil, beside the plants. The collected larvae were reared in laboratory conditions, fed by sugarcane seedlings. The biological cycle of L. alvarengai was completed in 230 days, displaying three larval instars with mean size of the cephalic capsule of 1.68, 2.46, and 3.00 mm for the first, second, and third instar, respectively. Adults were collected in greater numbers in December 2012, and first-instar larvae were observed as of January 2013. Conversely, pupae were observed in the field from July 2012 to January 2013. This is the first record of larvae and adults of L. alvarengai in sugarcane fields in Mato Grosso do Sul state, contributing with the knowledge about its biology and temporal distribution in the field.

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.

Pasture areas have been decreasing over the years in Brazil, largely due to the expansion of agricultural areas, mainly in the Southeast region. Natural or planted pastures are subject to attack by insects that can become pests depending on their level of infestation and among them are the Scarabaeidae beetles. The scarce information on the species of this family existing in the region of Bálsamo (São Paulo) makes a study on the occurrence of these species necessary, thus generating data that can contribute to identification and information on possible existing pest species. During September 2018 to August 2019, collections of phytophagous Scarabaeidae species were done in pasture areas with a light trap. A total of 446 adults from the subfamilies Dynastinae, Melolonthinae and Rutelinae were collected. In Dynastinae the genera Bothynus, Coelosis, Cyclocephala, Chalepides and Actinobolus were collected, in Melolonthinae the genera Plectris and Liogenys and in Rutelinae the genera Anomala, Geniates, Leucothyreus, Lobogeniates, Byrsopolis and Trizogeniates were found. Among the species collected, some are described as pests in crops, including pastures, such as Liogenys suturalis Blanchard, which was the species that had the largest number of individuals during the collection period, being indicated as a species worthy of more detailed studies.