Fábio Prezoto

Prey captured and used in Polistes versicolor (Olivier) (Hymenoptera: Vespidae) Nourishment

The social wasps are predators of many insect species and the study of their preys can reveal the potential of these natural enemies in biological control programs. A total of 240h of collections of preys in 32 nests of Polistes versicolor (Olivier) was carried on in Juiz de Fora, Minas Gerais State, Brazil, from March 2000 to February 2001. The preys captured by P. versicolor were mainly those from the orders Lepidoptera (95.4%) and Coleoptera (1.1%) while 3.4% of them were not identified. Chlosyne lacinia saundersii Doubleday & Hewitson (Lepidoptera: Nymphalidae) was the most collected prey (13.5%). The total of 4,015 preys was estimated to be captured per colony of P. versicolor during one year. The species can be used in integrated pest management of herbivorous insects, especially defoliating caterpillars.

Uso da vespa social Polistes versicolor no controle de desfolhadores de eucalipto

O objetivo deste trabalho foi determinar os recursos forrageados por Polistes versicolor em area de reflorestamento com eucalipto e identificar as presas forrageadas. No periodo de janeiro a dezembro de 2007, foram realizadas 24 observacoes da atividade forrageadora de colonias de P. versicolor presentes em um reflorestamento de eucalipto, em Juiz de Fora, MG, totalizando 240 horas de registros. Durante as dez horas de observacao diaria, foram registrados e qualificados, a cada 30 minutos, os retornos das operarias para a colonia. Foram registrados 1.809 retornos, dos quais 51,63% foram com nectar; 6,85%, com agua; 4,7%, com fibra vegetal; 17,41%, com presas; e 19,40%, sem recurso forrageado (improdutivos). As operarias de P. versicolor predaram exclusivamente lagartas de lepidopteros, que foram a unica fonte de proteina animal oferecida aos insetos imaturos, na colonia. Dessa forma, a especie estudada apresenta potencial como agente controlador biologico de herbivoros desfolhadores de eucalipto.

Sampling Methods for Assessing Social Wasps Species Diversity in a Eucalyptus Plantation

ABSTRACT Social wasps were collected in a eucalyptus (Eucalyptus urograndis, a genetically enhanced eucalyptus) plantation in Juiz de Fora, state of Minas Gerais, southwestern of Brazil, by using a variety of sampling methods, including active capture and baited traps set at two microhabitats. Six new records of social wasps for this region were obtained during the study: Brachygastra lecheguana Latreille, Polybia ignobilis Haliday, Polybia occidentalis Olivier, Polybia platycephala (Richards), Protonectarina sylveirae Saussure, and Protopolybia exigua Saussure (Hymenoptera: Vespidae). The active capture method sampled the greatest number of species. Baited traps installed in the canopy sampled a greater number of individuals of social wasps than those set on the trunks of eucalyptus trees. Fruit based baits captured a greater number of social wasp species than those baited with a protein derivative. Once no method was able to sample all species, we concluded that the efficiency of a survey can be maximized by using traps with a variety of different baits, in combination with active capture methods.

Survey of preys captured and used by Polybia platycephala (Richards) (Hymenoptera: Vespidae, Epiponini)

The social wasps are predators of several species of insects and the study of their preys can reveal their potential for programs of biological pest control. During the period of September 2000 to January 2002, were accomplished 70h of collections of the preys captured in twelve nests of Polybia platycephala Richards, placed in urban areas of Juiz de Fora municipality, Minas Gerais State, Brazil. The preys captured by P. platycephala include five orders of insects: Diptera (33.4%), Lepidoptera (28.6%), Hemiptera (12.0%), Hymenoptera (9.4%) e Coleoptera (7.2%). The mean weight of protein charge carried by the wasps was 1.9 ±1.6mg (n = 34, 0.3 - 6.2 mg), and the mean of protein transported per day was 22.8 mg. According to the results, we could estimate that 4,380 preys are captured by a single colony of P. platycephala during one year. Thus, this species could be used in management programs of urban pests, helping the equilibrium of this environment.

Flower-Visiting Social Wasps and Plants Interaction: Network Pattern and Environmental Complexity

Network analysis as a tool for ecological interactions studies has been widely used since last decade. However, there are few studies on the factors that shape network patterns in communities. In this sense, we compared the topological properties of the interaction network between flower-visiting social wasps and plants in two distinct phytophysiognomies in a Brazilian savanna (Riparian Forest and Rocky Grassland). Results showed that the landscapes differed in species richness and composition, and also the interaction networks between wasps and plants had different patterns. The network was more complex in the Riparian Forest, with a larger number of species and individuals and a greater amount of connections between them. The network specialization degree was more generalist in the Riparian Forest than in the Rocky Grassland. This result was corroborated by means of the nestedness index. In both networks was found asymmetry, with a large number of wasps per plant species. In general aspects, most wasps had low niche amplitude, visiting from one to three plant species. Our results suggest that differences in structural complexity of the environment directly influence the structure of the interaction network between flower-visiting social wasps and plants.

Paint marking social wasps: an evaluation of behavioral effects and toxicity

To make individual insect identification possible in markrecapture studies, researchers have employed various methods of artificial marking, including tags, mutilation, ink, dust, dye, pollen, genetic, radioactive-isotope, elemental, and protein marking (Haghler & Jackson, 2001; Haghler & Miller, 2002; Piper, 2002; Kobelt et al., 2009; Stephens et al., 2009). Inks are the most common materials for marking insects (Wineriter & Walker, 1984). They are applied to individuals with toothpicks, insect pins, fine-tipped pens or fine-haired brushes (Southwood, 1978). Among 26 inks tested on the surface of two cricket and one beetle species, oil-based inks had the greatest durability (Wineriter & Walker, 1984). These inks can be used to make a simple numbering system (Service, 1993; McIntosh et al., 1996) or elaborate coding systems (Brenner & Patterson, 1988) and inks are considered to be durable and easy to apply (McIntosh, 1999). Despite the advantages, these techniques are limited because (1) inks are often toxic to the insects (Southwood, 1978) and (2) marking techniques can affect insect behavior (Chang, 1946). The effect of insect marking has been neglected in social insects (bees, wasps, and ants), because of the large number of studies in which researchers used inks without testing for behavioral or toxic effects. The only known work was conducted by Packer (2005), which showed that two halictid bees, the solitary Penapis toroiRozen and the semisocial Corynura chloris (Spinola) alter their behavior after paint marking, under laboratory conditions. Marked pairs of C. chloris showed significantly more cooperative behavior than unmarked pairs and marked P. toroi showed significantly increased aggression and decreased cooperation. Many researchers have marked wasps with waterbased ACRILEX ink, a cheap, readily visible, quick-drying ink. Basic shortand long-term studies on sociobiology of wasps (De Souza et al., 2008, 2010a, 2011; Grazinoli et al., 2010; Sinzato et al., 2011) as well as applied short-term studies on the homing ability of wasps (Prezoto & Gobbi, 2005; De Souza et al., 2010b) have used this technique. Despite their use, they present the same problem as the other techniques for wasp identification: it is not known if inks have behavioral or toxic effects. Here, we tested whether marking inks can affect social wasp behavior under field conditions. If wasps alter their behavior after marking, it was expected that the addition of ink to the wasp body results in a significant increase in the frequency of grooming. Furthermore, possible effects of paint marking on the survival of laboratory-reared individuals of the eusocial wasp Polistes versicolor (Olivier) (Hymenoptera: Vespidae) were tested.

Flight range extension in Polistes simillimus Zikán, 1951 (Hymenoptera, Vespidae)

The aim of this study was to determine the flight range extension of the social wasps, Polistes simillimus. The results of the 125 wasps-carried out tests originating from 10 colonies in post-emergency stage demonstrated that the flight range extension of P. simillimus was of approximately 150m, resulting in a collection area of about 70.650m≤ by colony. It suggested wasp’s efficiency as a biological control agent.

Marine debris ingestion by sea turtles (Testudines) on the Brazilian coast: an underestimated threat?

Assessment of marine debris ingestion by sea turtles is important, especially to ensure their survival. From January to December 2011, 23 specimens of five species of sea turtles were found dead or dying after being rehabilitated, along the coast of the municipality of Rio de Janeiro, Brazil. To detect the presence of marine debris in the digestive tract of these turtles, we conducted a postmortem examination from the esophagus until the distal portion of the large intestine for each specimen. Of the total number of turtles, 39% had ingested marine debris such as soft plastic, hard plastic, metal, polyethylene terephthalate (PET) bottle caps, human hair, tampons, and latex condoms. Five of the seven sea turtles species are found along the Brazilian coast, where they feed and breed. A large number of animals are exposed to various kinds of threats, including debris ingestion.

Regulation of worker activity in the social wasp Polistes versicolor

In simple societies, activity of the workers can be regulated in a centralized way by a sole individual. Polistes wasps are simple in some respects because they have small, open colonies, with a single queen who is not morphologically differentiated from the workers. Worker activity in Polistes is episodic. Pause periods are followed by periods of intense activity, when most individuals are in motion. One way to investigate the regulation of worker activity is to see if activity periods are initiated by one specific individual. The queen was found regulating the resumption of activity in P. fuscatus in a centralized way, but recently, a decentralized regulation was found in P. instabilis and P. dominula. Thus, what is the pattern of regulation of worker activity in Polistes? To solve this question, broader studies of other species are desirable. Therefore, we investigated whether activity of P. versicolor workers are regulated by one individual. We tested for two mechanisms: triggering periods of colonial activity or actually physically stimulating workers to forage. The results demonstrated that no single individual was responsible to start periods of activity or physically stimulate worker’s departure. P. versicolor appears to be an example of a society with an intermediary organization of work, where the queen controls reproduction but does not organize work.

Foundation pattern, productivity and colony success of the paper wasp, Polistes versicolor

Abstract Polistes versicolor (Olivier) (Hymenoptera: Vespidae) colonies are easily found in anthropic environments; however there is little information available on biological, ecological and behavioral interactions of this species under these environmental conditions. The objective of this work was to characterize the foundation pattern, the productivity, and the success of colonies of P. versicolor in anthropic environments. From August 2003 to December 2004, several colonies were studied in the municipal district of Juiz de Fora, Southeastern Brazil. It was possible to determine that before the beginning of nest construction the foundress accomplishes recognition flights in the selected area, and later begins the construction of the peduncle and the first cell. As soon as new cells are built, the hexagonal outlines appear and the peduncle is reinforced. Foundation of nests on gypsum plaster was significantly larger (p < 0.0001; &khgr;2 test) in relation to the other types of substrate, revealing the synantropism of the species. On average, the P. versicolor nest presents 244.2 ± 89.5 (100–493) cells and a medium production of 171.67 ± 109.94 (37–660) adults. Cells that produced six individuals were verified. Usually, new colonies were founded by an association of females, responsible for the success of 51.5%. Although these results enlarge knowledge on the foundation pattern of P. versicolor in anthropic environments, other aspects of the foundation process require further investigation.