Revista Brasileira de Entomologia 60 (2016) 248–254 REVISTA BRASILEIRA DE Entomologia A Journal on Insect Diversity and Evolution www.rbentomologia.com Biology, Ecology and Diversity Flight patterns and sex ratio of beetles of the subfamily Dynastinae (Coleoptera, Melolonthidae) a,∗ b a Larissa Simões Corrêa de Albuquerque , Paschoal Coelho Grossi , Luciana Iannuzzi a Universidade Federal de Pernambuco, Departamento de Zoologia, Recife, PE, Brazil b Universidade Federal Rural de Pernambuco, Departamento de Agronomia/Protec¸ ão de Plantas, Recife, PE, Brazil a r a b s t r a c t t i c l e i n f o Article history: Dynastinae is one of the most representative subfamilies of Melolonthidae (Scarabaeoidea) and has Received 8 July 2015 considerable ecological importance due mainly to interactions with plants of the families Araceae and Accepted 24 March 2016 Annonaceae. This relationship has led to the evolution of nocturnal activity patterns, which are influenced Available online 13 May 2016 by environmental conditions. In the present study, abiotic factors were investigated to comprehend the Associate Editor: Rodrigo Krüger influence on the flight patterns and identify the sex ratio of beetles from this subfamily. A study was con- ducted at Campo de Instruc¸ ão Marechal Newton Cavalcanti in northeastern Brazil between December Keywords: 2010 and November 2011. Thirteen species of Dynastinae were identified, most of which were from the Brazilian Atlantic forest genus Cyclocephala. Abundance and richness were greater in the dry season. Six species exhibited peak Cyclocephalini flight activity at specific periods of the night. More females than males were recorded for Cyclocephala Light trap distincta and C. paraguayensis. The present findings suggest that rainfall reduces the flight activity of Nocturnal beetles these beetles and different time schedules may be related to mating behavior, foraging behavior and the avoidance of interspecific resource competition. © 2016 Sociedade Brasileira de Entomologia. Published by Elsevier Editora Ltda. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Introduction Nocturnal or crepuscular habits are associated with anthophilia, especially for Cyclocephalini (Endrödi, 1985; Gottsberger, 1999, Dynastinae is one of the most remarkable subfamilies of 1986; Maia and Schlindwein, 2006; Maia et al., 2012, 2010). The pol- Melolonthidae sensu Endrödi (1966). Beetles of this subfamily occur lination of many tropical fruit trees that have night anthesis, such as in nearly all major biogeographic regions and are mostly found in Annona spp. (Annonaceae), palms (Arecaceae) and aroids (Araceae), the tropics, especially the Neotropics (Ratcliffe, 2003). Adults feed is dependent on pollinating beetles, especially species of the genera on decomposed fruits, algae, plants roots (obtaining nutritive liq- Cyclocephala Latreille and Erioscelis Burmeister, which ensure the uids), leaves, flowers and pollen (Jackson and Klein, 2006; Ritcher, reproductive success of these trees (Endrödi, 1985; Gottsberger, 1958).Nearly all Dynastinae adults are either nocturnal or crepus- 1986, 1999; Silberbauer-Gottsberger et al., 2003; García-Robledo cular (Ratcliffe, 2003; Riehs, 2006; Ratcliffe and Cave, 2009). Diurnal et al., 2004; Croat, 2004; Maia and Schlindwein, 2006; Ratcliffe, activity corresponds to the interval of time used for foraging and 2008, 2003; Maia et al., 2012, 2010). mating and is defined by the presence of sunlight (Pianka, 1973; In tropical rainforests, insect species are influenced by biotic Manosa˜ et al., 2004; Hernández, 2007; González-Maya et al., 2009). and abiotic oscillations (Emmel and Leck, 1970; Wolda, 1989; Nair, In general, peak activity in species is regulated by different factors 2007). Rainfall, food sources and predators exert an influence on (Hernández, 2007, 2002; Feer and Pincebourne, 2005; Gillet et al., the abundance of tropical insects (Wolda, 1988, 1978). Favorable 2010; Gerber et al., 2012). Predators and food sources, for instance, environmental conditions facilitate the growth, reproduction and act as regulators of peak activity, leading to adaptations that result activity of these organisms (Tauber et al., 1986; Wolda, 1988). in the success and survival of organisms (Pianka, 1973; Dawkings Environmental conditions also exert an influence on the sex and Krebs, 1979; Overdorff, 1988; Gill, 1991; González-Maya et al., ratio of insects (Hamilton, 1967). In response to variations in envi- 2009; Halffter and Halffter, 2009; Valera et al., 2011). ronmental conditions, the sex ratio of the offspring varies due to changes in fitness (West and Sheldon, 2002). Depending on off- spring competition of one sex with another and the parents, a ∗ tendency to produce the other sex occurs to avoid the effect of local Corresponding author. resource competition (Taylor, 1994; Julliard, 2000). In poor-quality E-mail: [email protected] (L.S.C.d. Albuquerque). http://dx.doi.org/10.1016/j.rbe.2016.03.002 0085-5626/© 2016 Sociedade Brasileira de Entomologia. Published by Elsevier Editora Ltda. This is an open access article under the CC BY-NC-ND license (http:// creativecommons.org/licenses/by-nc-nd/4.0/). L.S.C.d. Albuquerque et al. / Revista Brasileira de Entomologia 60 (2016) 248–254 249 environments, parental individuals may increase fitness by biasing sampling point using a digital thermo hygrometer. Readings were their offspring more toward a dispersing sex (Julliard, 2000). taken on the sampling day between 5:00 pm and 5:00 am. Consider- Despite the importance of beetles of the subfamily Dynasti- ing the historical precipitation index, the rainy season was defined nae as pollinators and their role in maintaining healthy edaphic as spanning from March to August (ITEP/HIDROMET, 2012). ecosystems, few studies have addressed the biodiversity and nat- ural history of these beetles, especially in the Atlantic Rainforest Insect sampling north of the São Francisco River Basin in northeastern Brazil. Thus, the aim of the present study was to determine the effects of rain- Beetles of the subfamily Dynastinae were collected monthly fall of beetle communities of the subfamily Dynastinae and identify from December 2010 to November 2011, except April 2011, due to nocturnal flight activity and the sex ratio of the species collected. intense rainfall that prevented access to the collection site. Samp- The hypotheses are that differences in abundance and richness ling lasted 12 h and was performed every 30 days. The sample site occur between the dry and rainy seasons; peak flight activity is was established at a distance of 30 m from the edge of the remnant related to foraging behavior and the sex ratio denotes similar pro- of the Atlantic rainforest. portions of males and females. A light trap was installed to attract beetles from 5:00 pm to 5:00 am the following day. Black light (250 W) and mixed mercury Material and methods vapor bulbs (250 W) were deployed on opposite sides of a white sheet measuring 2.3 m × 2.0 m, stretched at the collection point Study site (Fig. 2A–C). The beetles were collected manually as they landed on the illuminated sheet. This study was conducted in the municipality of Abreu e Lima (state of Pernanbuco, northeastern Brazil) at the Campo de ◦ Instruc¸ ão Marechal Newton Cavalcanti (CIMNC – 7 49 49.39 S, ◦ 35 6 10.20 W), which is a military site located in the Aldeia- Beberibe Environmental Protection Area, covering 30,000 ha (SEMAS, 2012) (Fig. 1A–C). The CIMNC is located 40 km NW of the coast and has a total of 7324 ha (Andrade et al., 2005; Lucena, 2009). Vegetation consists of open tropical rainforest and semi-deciduous A forest, comprising secondary forest with a few remnants of pri- B mary forest (Andrade et al., 2005; Lucena, 2009; IBGE, 2012). This 2.0m site was formerly a sugar cane mill that was intensively exploited until the establishment of the CIMNC in 1944 (Andrade et al., 2005; Lucena, 2009; Guimarães et al., 2012). It is currently preserved by C the Brazilian Army (Lucena, 2009). Abioctic data 2.3m Daily and monthly rainfall indices from 2010 to 2011 were obtained from hydro-meteorological monitoring unit of the Labo- 2.3m ratório de Meteorologia de Pernambuco (ITEP/HIDROMET, 2012). Historical mean rainfall and monthly mean temperature were obtained from the Abreu e Lima Station (ITEP/HIDROMET, 2012). Fig. 2. Light trap model used for beetle sampling: (A) Black light bulb. (B) Mixed Other temperature and humidity data were obtained at the mercury bulb. (C) Light support. Fig. 1. Map showing sampling site: (A) Pernambuco State represented in black. (B) Black dot representing Campo de Instruc¸ ão Marechal Newton Cavalcanti, Abreu e Lima, Pernambuco, Brazil. (C) Black dot representing sampling site at Marechal Newton Cavalcanti, Abreu e Lima, Pernambuco, Brazil. 250 L.S.C.d. Albuquerque et al. / Revista Brasileira de Entomologia 60 (2016) 248–254 Table 1 Total and relative abundance of nocturnal species of Dynastinae (Coleoptera, Melolonthidae) at Campo de Instruc¸ ão Marechal Newton Cavalcanti over one year of collection (2010–2011). Tribe Species Abundance Relative abundance (%) Cyclocephalini Cyclocephala cearae Höhne, 1923 19 4.2 Cyclocephalini Cyclocephala distincta Burmeister, 1847 266 58.3 Cyclocephalini Cyclocephala paraguayensis Arrow, 1913 63 13.8 Cyclocephalini Cyclocephala vestita Höhne, 1923 2 0.4 Cyclocephalini Dyscinetus dubius (Olivier, 1789) 27 6 Cyclocephalini Dyscinetus rugifrons (Burmeister, 1847) 10 2.2 Cyclocephalini Chalepides sp. 1 0.2 Cyclocephalini Stenocrates holomelanus (Germar, 1824) 28 6.1 Pentodontini Eutheola humilis (Burmeister, 1847) 1 0.2 Pentodontini Tomarus ebenus (De Geer, 1774) 10 2.2 Pentodontini Ligyrus (Ligyrus) cuniculus (Fabricius, 1801) 27 6 Oryctini Strategus validus (Fabricius, 1775) 1 0.2 Oryctini Coelosis bicornis (Leske, 1779) 1 0.2 Total 456 100 For each hour of collection, a killing jar (polypropylene jar with A 30 ethyl acetate) was used to record of flight period. The samples 25 were taken to laboratory of Taxonomia e Ecologia de Insetos of the SE) Universidade Federal de Pernambuco for taxonomic identification.