Leonardo Gomes

A preliminary study of insect fauna on pig carcasses located in sugarcane in winter in southeastern Brazil

Minimum post‐mortem intervals can be estimated based on analyses of the pattern of insect succession on a carcass. In order to successfully apply this approach, insect development rates must be considered with regard to local regional climatic conditions. This study is the first to analyse insect succession on carcasses decomposing in a sugarcane crop in Brazil. In all seasons, Chrysomya albiceps (Wiedemann) (Diptera: Calliphoridae) and Cochliomyia macellaria (Fabricius) were frequent visitors during the fresh and bloated stages of decomposition, whereas Dermestes maculatus (De Geer) (Coleoptera: Dermistdae), Necrobia rufipes (De Geer) (Coleoptera: Cleridae) and Oxelytrum sp. (Coleoptera: Silphidae) were characteristic at the most advanced decomposition stages. The fact that climatic variations influence the occurrence of insect species and vegetation in the tropics may help to solve crimes through sampling of the local insect fauna, as may the fact that only certain groups of insects occur in specific regions of large countries like Brazil.

Occurrence of Hymenoptera on Sus scrofa carcasses during summer and winter seasons in southeastern Brazil

Considerable importance has been given to nest construction and larval food transport to the nest as a precondition for the eusociality of insects. Most adult hymenopterans feed on liquids, although bees and a few wasps may also feed on pollen. Carrion represents an additional source of protein for some species and they will scavenge for dead animals in the wild. This paper aims at analyzing Hymenoptera visitors on a pig carcass during the process of decomposition, in the summer of 2005 and the winter of 2006 in Brazil, and comparing the results with other studies in the Neotropical region. To our knowledge, this is the first study which described the occurence of Agelaia pallipes, Polybia paulista and Scaptotrigona depilis on decomposing carcasses in southeastern Brazil. It also raises the hypothesis of possible applications of Hymenoptera to achieve more precise PMI estimations, apart from other insects already known as having great importance in such estimates.

Dispersal and burial behavior in larvae of Chrysomya megacephala and Chrysomya albiceps (Diptera, Calliphoridae)

Blowflies use discrete and ephemeral substrates to feed their larva. After they run out of food, the larvae begin to disperse in order to find adequate places for pupation or additional food sources, a process named post-feeding larval dispersal. Briefly state the aspects and why they are important were studied in a circular arena of 25 cm in diameter and covered with wood shavings to a height of 40 cm allowing post-feeding dispersal from the center of the arena. Larvae of both Chrysomya albiceps and C. megacephala were used in five experiments for each species. For each pupa location, determined as distance from the center, depth, and weight were evaluated. Statistical tests were done to verify the relation between weight, depth and distance for pupation and for larvae of two species shows that the media distance is significantly different for two species and for C. megacephala this distance is greater than the distance for C. albiceps. The depth too is different for each species, as the larvae of C. megacephala buries deeper than C. albiceps. With relation of weight, there is no statistic evidence that have any difference between weights for pupation for each species.

Dispersão larval radial pós-alimentar em Lucilia cuprina (Diptera, Calliphoridae): profundidade, peso e distância de enterramento para pupação

Blowflies utilize discrete and ephemeral sites for breeding and larval nutrition. After the exhaustion of food, the larvae begin dispersing to search for sites to pupate or for additional food source, process referred as postfeeding larval dispersal. Some aspects of this process were investigated in Lucilia cuprina (Wiedemann, 1830), utilizing a circular arena to permit the radial dispersion of larvae from the food source in the center. To determine the localization of each pupa, the arena was split into 72 equal sectors from the center. For each pupa, distance from the center of arena, weight and depth were determined. Statistical tests were performed to verify the relation among weight, depth and distance of burying for pupation. It was verified that the larvae that disperse farthest are those with lowest weights. The majority of individuals reached the depth of burying for pupation between 7 and 18 cm. The study of this process of dispersion can be utilized in the estimation of postmortem interval (PMI) for human corpses in medico-criminal investigations.

Foraging by Polybia (Trichothorax) ignobilis (Hymenoptera, Vespidae) on flies at animal carcasses

Foraging by Polybia (Trichothorax) ignobilis (Hymenoptera, Vespidae) on flies at animal carcasses. Proteins for brood nutrition of social wasps are obtained from many prey, including insects (even bees and other wasps), spiders and bits of decaying meat. After being captured and killed, prey are reduced to a shapeless mass and distributed to the brood. Little is known about the foraging activity, especially on this group. Herein we describe the sequence of foraging behaviours of the social wasp Polybia (Trichothorax) ignobilis for hunting flies (Diptera: Calliphoridae and Muscidae) over pig carcasses. To our knowledge, there are few scientific descriptions of prey foraging behaviour on this species.

Estudo da dispersão larval radial pós-alimentar em Chrysomya megacephala (Fabricius) (Diptera, Calliphoridae)

Blowflies utilize discrete and ephemeral sites for breeding and larval nutrition. After the exhaustion of food, the larvae begin dispersing to search for sites to pupate or to additional food source, process referred as postfeeding larval dispersal. Some of the most important aspects of this process were investigated in Chrysomya megacephala, utilizing a circular arena to permit the radial dispersion of larvae from the center. To determinate the localization of each pupa, the arena was split in 72 equal sectors from the center. For each pupa, distance from the center of arena, weight and depth were determined. Statistical tests were performed to verify the relation among weight, depth and distance of burying for pupation. It was verified that the larvae that disperse farther are those with higher weights. The majority of individuals reached the depth of burying for pupation between 7 and 18 cm. The study of this process of dispersion can be utilized in the estimation of postmortem interval (PMI) for human corpses in medico-criminal investigations.

The Influence of Temperature on the Behavior of Burrowing in Larvae of the Blowflies, Chrysomya albiceps and Lucilia cuprina, Under Controlled Conditions

Abstract Blowflies use discrete, ephemeral substrates for larval development. After exhaustion of the food supply, larvae will disperse in search of sites to burrow and pupate or will seek other sources of food in a process known as post-feeding larval dispersal. In this study, the effect of temperature was investigated as it is one of the most important aspects of the environmental variables in this process. 800 larvae of the blowflies Chrysomya albiceps (Wiedemann 1819) and Lucilia cuprina (Wiedemann 1830) (Diptera: Calliphoridae) were incubated in tubes covered with vermiculite at 15, 20, 25 and 30°C. For each pupa, the body weight, sex and depth of burrowing were determined. Statistical tests were used to examine the relationship of depth of burrowing and body weight to the temperature at which burrowing occurred. Depth of burrowing was affected differently by temperature for both of the species studied; L. cuprina larvae burrowed deeper at lower and higher temperatures while C. albiceps larvae burrowed less at extreme temperatures. Additionally, temperature had a significant effect on the body weight of L. cuprina larvae as body weight decreased as temperature increased, whereas for C. albiceps, pupal weight increased up to 25°C and then decreased abruptly at a higher temperatures. The maximum body weight was also differently affected in the two species; in L. cuprina, the maximal weight was at 15°C and for C. albiceps weight was maximal at 20°C.

Behavior of the combined radial post-feeding larval dispersal of the blowflies Chrysomya megacephala and Chrysomya albiceps (Diptera, Calliphoridae) and implications for forensic entomology

The aims of this work was to study the life stages of Chrysomya megacephala in a circular arena allowing the combined radial post-feeding dispersal from the center of the arena of C. albiceps and C. megacephala larvae. To determine the location of each pupa, the distance from the center, the depth and weight of each pupa formed were analyzed. For the larvae of C. albiceps, females released buried deeper than males, reaching an average depth of 10.74 cm and C. megacephala larvae presented greater average results than C. albiceps for all variables, particularly distance, which was 16.02 cm for this species and 12.30 cm for C. albiceps. C. albiceps larvae preyed on 30 C. megacephala larvae in both experiments. These results could be used in forensic entomology because the evaluation of Post Mortem Interval (PMI) was one of the most important aspects of legal medicine, and it could be underestimated if the older dispersing larvae or those that dispersed longer and faster or deeper, were not taken into account.

Efeito da semeadura a seco e tratamento de sementes na emergência, rendimento de grãos e outras características da soja [Glycine max (L.) Merrill]

O trabalho foi conduzido na Universidade Federal de Lavras-MG, em um Latossolo Roxo distrofico, no ano agricola 94/95. Utilizou-se o delineamento blocos casualizados em esquema fatorial 2 x 4, compreendendo: semente tratada com fungicida Vitavax/Thiram P.M.e nao tratada, e quatro periodos de seca (0, 7, 14 e 21 dias apos a semeadura). A semeadura foi realizada em solo seco (6% de umidade), utilizando-se a cultivar Doko. As sementes apresentaram otima performance ate 14 dias, nao sendo alterado o rendimento de graos, proporcionando ao agricultor uma maior elasticidade na data da semeadura. Os tratamentos fungicidas, por sua vez, apesar de alterarem significativamente o estande inicial e final, nao proporcionaram aumentos no rendimento de graos.

Adubação foliar: I. Épocas de aplicação de fósforo na cultura da soja

A busca de novas alternativas para o aumento da produtividade da soja tem sido constante objetivo de pesquisadores e produtores. As respostas da cultura a aplicacao do fosforo via solo sao bem definidas, sendo esse nutriente de grande importância no desenvolvimento da mesma, implicando seu uso em aumento do rendimento. A adubacao foliar nessa cultura vem sendo muito difundida por empresas deste ramo, surgindo como uma opcao viavel de fornecimento suplementar de nutrientes, principalmente quando constatados niveis baixos na planta em caso de deficiencias. Visando dar maiores subsidios aos produtores, objetivou-se com este trabalho estudar o efeito da adubacao foliar de fosforo aplicado em diferentes estadios da planta compreendendo: V5, R1, R4, V5+R1, V5+R4, R1+R4, V5+R1+R4, V5+R1+R4+R6 e tratamento testemunha. O ensaio foi implantado em uma lavoura de soja, cultivar Monarca, na Fazenda Palmital em Ijaci-MG, utilizando delineamento de blocos casualizados com 9 tratamentos e tres repeticoes. Foi utilizado como fonte de fosforo o produto Quimifol P30 quelatizado na forma liquidacom 30 % do nutriente soluvel em CNA + agua na dose de 2,0 l.ha-1sendo as aplicacoes realizadas com pulverizador costal de gas carbonico, bico leque, a pressao constante de 2,8 kgf/cm2. As diferentes epocas de aplicacao de fosforo alteraram significativamente o rendimento de graos, proporcionando aumentos significativos de ate 16% para as epocas V5, V5 + R1, V5 + R4, V5 + R1 + R4, V5 + R1 + R4 + R6, quando comparados a testemunha, expressando claramente o efeito positivo dessas aplicacoes na epoca V5. As caracteristicas altura da planta, insercao do 1o legume e indice de acamamento nao foram alteradas significativamente pelas diferentes epocas avaliadas. Observou-se resposta significativa para os teores foliares de nutrientes somente para os indices de K e Zn, exclusivamente no tratamento V5+R4, e nas epocas V5, V5 + R1 e V5 + R1 + R4 + R6 respectivamente.