Relationship among Apis mellifera L. stings, swarming and climate conditions in the city of Rio Claro, SP, Brazil

The presence of bees (Apis mellifera L.) in urban areas has increased in recent years due to environmental disturbances caused by humans. Bee migration to cities may provoke serious accidents, since some people present allergic reactions to their venoms. In Rio Claro city, São Paulo state, Brazil, the number of calls to the fire brigade for removal of bee swarms, and the number admissions in local hospitals due to bee stings were investigated during 2002 and 2003, and a correlation between these data and the average temperature, rainfall and relative humidity was found. The study period was divided into three phases according to the number of times that the fire brigade was called to remove swarms (263 times): January to July 2002 - 51 calls (19.39 percent); August 2002 to July 2003 - 140 calls (53.23 percent); and August to December 2003 - 72 calls (27.38 percent). A significant correlation among the number of calls, the local temperature and rainfall was detected. The number of accidents was not associated with environmental variables. Based on the current results, public activities for prevention of bee attacks may be developed to avoid unwanted contact between humans and these insects, and/or provide the appropriate management of the colonies.

Hymenoptera marking technique

In true social hymenopterans, such as many species of bees, wasps and all species of ants, the main characteristics are the overlapping of generations, the care with the offspring and the division of labor among the members of the colony. The first biological feature means that in a same moment there are groups of individuals, with variable ages, that execute different activities in the colony. In order to study the division of labor among the members of the colony, or to estimate the life span of these insects, or even to analyze any kind of behavior in non-social insects, it is necessary to know the exact age of each individual. For this reason, the insects must be identified soon after emergence. The identification of insects with numbers is an important technological improvement in behavioral studies, mainly in honeybee colonies. The aim of this scientific note is to describe an easy and cheaper technique for marking hymenopterans.

Oviposition sequence and offspring of mated and virgin females of Cotesia flavipes (hymenoptera: braconidae) parasitizing Diatraea saccharalis larvae (lepidoptera: crambidae)

Large scale mass rearing of natural enemies has been a mean of improving biological control in the sugarcane intensive agriculture. Among them, Cotesia flavipes, a gregarious koinobiont endoparasitoid, was imported by Brasil to control caterpillars of the sugarcane borer Diatraea saccharalis. The C. flavipes larval development depends on its association with polydnavirus, which blocks the host defense reaction. To verify if the oviposition sequence (1st, 2nd or 3rd) and the female condition (mated or virgin) interfere in the number of C. flavipes descendents, 4th instar caterpillars of D. saccharalis were parasitized. Analysis of the data showed that: a) there is an inverse correlation between the parasitism efficiency and the host reaction (encapsulation); b) the number of caterpillars parasitized by virgin females that released parasitoid larvae in the period from 12 to 15 days was higher than that of caterpillars parasitized by mated females; c) a slight difference between mated and virgin females in relation to the parasitim success was observed; and d) the number of encapsulated parasitoid larvae was higher than that of eggs, suggesting that eggs have a better capacity to overcome the host reaction. In this study, the viability of C. flavipes eggs and larvae in the non-specific host D. saccharalis could be correlated with the oviposition sequence and the female condition

Body size and flight distance in stingless bees (Hymenoptera: Meliponini): inference of flight range and possible ecological implications

Neste trabalho analisamos as implicações espaciais da distância máxima de vôo para algumas espécies de meliponíneos. Os dados sugerem que a distância máxima de vôo em meliponíneos está relacionada ao tamanho do corpo, especialmente ao tamanho generalizado das asas, que pode ser estimado utilizando análises de componentes principais. Uma análise utilizando seis espécies de meliponíneos evidenciou que o tamanho generalizado das asas está fortemente correlacionado à distância de vôo (r = 0,938). Isso sugere que espécies de meliponíneos ocupam área efetivamente maior quanto maior for o tamanho do corpo, trazendo importantes implicações para a dinâmica espacial de populações locais restritas a áreas fragmentadas. Neste trabalho, também utilizamos um modelo de regressão linear a fim de estimar as distâncias máximas de vôo para 12 outras espécies de meliponíneos. Esta pesquisa fornece subsídios para futuros estudos relacionados à conservação da biodiversidade.

Body size and flight distance in stingless bees (Hymenoptera: Meliponini): inference of flight range and possible ecological implications

We examined the spatial implications of maximum flight distance for several species of stingless bees. Data suggested that maximum flight distance in Meliponini is a function of body size, especially generalized wing size, which can be estimated through principal component analysis. For six species of stingless bees, flight distances and generalized wing sizes were highly correlated (r = 0.938). This indicates that species of Meliponini occupy an effectively larger area as body size increases, which has important implications in the spatial dynamics of local populations restricted to forest fragments. We also used the fitted linear regression model to estimate the maximum flight distance for 12 other species of Meliponini. The results of this research may provide insights for future studies of biological conservation.

Neste trabalho analisamos as implicações espaciais da distância máxima de vôo para algumas espécies de meliponíneos. Os dados sugerem que a distância máxima de vôo em meliponíneos está relacionada ao tamanho do corpo, especialmente ao tamanho generalizado das asas, que pode ser estimado utilizando análises de componentes principais. Uma análise utilizando seis espécies de meliponíneos evidenciou que o tamanho generalizado das asas está fortemente correlacionado à distância de vôo (r = 0,938). Isso sugere que espécies de meliponíneos ocupam área efetivamente maior quanto maior for o tamanho do corpo, trazendo importantes implicações para a dinâmica espacial de populações locais restritas a áreas fragmentadas. Neste trabalho, também utilizamos um modelo de regressão linear a fim de estimar as distâncias máximas de vôo para 12 outras espécies de meliponíneos. Esta pesquisa fornece subsídios para futuros estudos relacionados à conservação da biodiversidade.

Haemolymph electrophoretic pattern of Ascia monuste orseis larvae (Lepidoptera: Pieridae) parasitized by Cotesia glomerata (Hymenoptera: Braconidae)

Cotesia glomerata is a natural enemy of the vegetable plague Ascia monuste orseis and preferably parasites 2nd, 3rd and 4th instar larvae. Parasitism effects on the haemolymph protein profile of Ascia monuste orseis larvae from the 2nd to 7th days were analyzed both qualitatively and quantitatively by SDS-PAGE and Coomassie-Blue binding methods. Quantitative analysis showed a progressive increase in the protein content of about 6.5 and 12.5 times in parasitized and non-parasitized larvae from the 2nd to 5th days, respectively. On the 6th day, a decrease in protein content was observed in both groups, although this decrease was significantly less than the control group that continued to metamorphosis. Meanwhile, parasitized larvae had one more day (7th day) in their larval period to complete parasitoid development, justified by the fact that parasitoid is koinobiont and allows host feeding. On this day, a drastic increase in protein content was detected when the parasitoids left the host. The SDS-PAGE showed proteins of high molecular weight (>120 kDa) on the 5th day of the non-parasitized larvae when they entered pre-pupa stage and on the 7th day of parasitized larvae. Proteins with MW lower than 62 kDa and higher than 27 kDa were absent on the 5th day in control larvae (pre-pupa phase), but present in parasitized larvae. This could indicate a possible relation between these proteins and the host juvenile hormone. Therefore, the presence of C. glomerata influences Ascia monuste orseis development, but its own physiological development is apparently independent of the host, which tends to die when parasitism succeeds.

Chemical communication in Apis mellifera: temporal modulation of alarm behaviors

The effect of pheromones and their chemical analogues in honeybee alarm behaviors was studied in observation boxes. Defensive behaviors, as follows: a) attraction to scent source, b) elevation of wings in "V", c) abdomen elevation d) abdomen elevation and pumping and e) first leg pair elevation had been temporarily registered when the following compounds were presented: isoamyl alcohol, octyl alcohol, benzyl alcohol, n-butyl acetate, n-octyl acetate, isopentyl acetate, benzyl acetate and 2-heptanone. The results were as follows: 1. the bees elicited some characteristic behaviors when chemical alarm messages were presented, 2. agression (stinging) was not completed with any compound tested, probably because there was not a target (visual stimulus), 3. in all situations the attraction to scent source was low, 4. all the behaviors were elicited in a temporarily different way, 5. the compounds that elicited stronger responses and a greater number of the investigated behaviors were: isopentyl acetate, 2-heptanone, octyl acetate and n-octyl alcohol. In all situations, the first behavior response (and the most intense one) was the elevation and pumping the abdomen. This suggests that the chemical message was promptly recognized and then transmitted to each worker. So, the results obtained in the present work, suggest that chemical alarm messages may be recognized by different mechanisms of neural integration.

Molecular exclusion chromatography of crude venom as an auxiliary tool to identify hybrid honeybee populations

A comparison among the profiles of molecular exclusion chromatography in Sephadex G 100 column of venoms from Apis mellifera adansonii and Africanized honeybees revealed unique peaks which might be used to identify these populations. The venoms from hybrid populations resulting from the reciprocal mating of Apis mellifera adansonii and Africanized honeybees presented unique peaks, probably resulting from a synergistic effect between the parental genomes. The occurrence of characteristic peaks in venoms of hybrid populations might be used to identify these populations as well as to distinguish them from their parents.