Venom production by Africanized honeybees (Apis mellifera) and Africanized-European hybrids

Original paper

VENOM PRODUCTION BY AFRICANIZED HONEYBEES (Apis mellifera) AND AFRICANIZED-EUROPEAN HYBRIDS

S. R. C. FUNARI1,4, P. R. ZEIDLER¹, H. C. ROCHA², J.M. SFORCIN^3,4

1 Department of Production and Exploration Animal-School of Veterinary Medicine and Animal Husbandry, UNESP, Botucatu, State of São Paulo, Brazil; 2 School of Agronomy and Veterinary Medicine, UPF, Passo Fundo, State of Rio Grande do Sul, Brazil; 3 Department of Microbiology and Immunology- Biosciences Institute, UNESP, Botucatu, State of São Paulo, Brazil; 4 Center for the Study of Venoms and Venomous Animals-CEVAP-UNESP, State of São Paulo, Brazil.

ABSTRACT: This study used 15 beehives: five with Africanized queens sisters (Apis mellifera), five with Italian queens sisters (Apis mellifera ligustica), and five with Carniolan queens sisters (Apis mellifera carnica). The queens were fertilized naturally. This experiment was performed in the apiary of the Botucatu School of Veterinary Medicine and Animal Husbandry, UNESP, State of São Paulo, Brazil. The following data were obtained from the foraging bees: venom quantity in reservoir, 0.117±0.015, 0.139±0.020, and 0.147±0.024 (mg); venom quantity liberated in extraction apparatus, 0.073±0.012, 0.057±0.011 and 0.059±0.013 (mg); and sting electro stimulus threshold (volts), 10.75±1.37, 15.11±2.00, and 15.01±1.63 for Africanized, Italian x Africanized and Carniolan x Africanized, respectively. The Africanized honeybees possess less venom in reservoir than the European hybrids (Carniolan and Italian). However, they liberated a larger quantity of venom in the extraction apparatus and required lower electro stimulus threshold to promote stinging.

KEY WORDS: Venom reservoir, Apis mellifera scutellata, defensive behavior, venom extraction apparatus, Africanized honeybees, Carniolan honeybees, Italian honeybees.

INTRODUCTION

The honeybee Apis mellifera L. is a eusocial insect, showing behavioral patterns of social interaction between colony members. One example is colony defense, which is composed of a complex sequence of actions, which may include stinging (6).

Honeybee defensive behavior is affected by genetic composition (3,4,5,7,8,11,13,15) and modified by external factors such as smoke, pheromones or other volatile chemical substances, the presence or absence of other bees (12,19), and changes in the air electric load and environmental conditions (1,2,9,16,17).

The aim of this paper is to compare the quantity of venom in reservoir, the quantity of venom liberated in extraction apparatus, and electro stimulus threshold to promote stinging of Africanized and European hybrid foraging honeybees.

MATERIALS AND METHODS

Fifteen beehives were used: five with Africanized queens sisters (Apis mellifera), five with Italian queens sisters (Apis mellifera ligustica), and five with Carniolan queens sisters (Apis mellifera carnica). The queens were fertilized in naturally. This experiment was performed in the apiary of the Botucatu School of Veterinary Medicine and Animal Husbandry, UNESP, State of São Paulo, Brazil. The following data were obtained from the foraging bees:

Venom quantity in reservoir (mg). One hundred foraging bees were collected from each colony. The method to quantify the venom was adapted from Nogueira (14). Venom reservoirs from 10 workers were opened onto a glass slide. After 48 hours, the dry venom was weighed to obtain the mean amount of venom per bee.

Quantity of venom liberated in extraction apparatus (mg). One hundred foraging bees were collected from each colony. Ten bees were induced to sting onto a glass slide. After 48 hours, the slides were weighed to obtain the mean quantity of venom liberated by the extraction process.

Electro stimulus threshold to promote stinging. Ten foraging bees were collected from each colony and were tested for sting readiness, according to Kolmes and Fergusson-Kolmes (10).

Analysis of variance was used for hierarchical models with tests of hypotheses. Treatment effect and beehive effect in each treatment were submitted to calculation of statistical F and p-value. The Tukey Test and Descriptive Statistics were used for calculating average (x), standard deviation (SD), and coefficient of variation (CV) (20).

RESULTS AND DISCUSSION

Quantity of venom in reservoir (mg). The Africanized bees presented smaller quantities in reservoir (0.117±0.015 mg of dry venom) than both the hybrids Carniolan (0.147±0.024 mg) and Italian (0.139±0.020 mg) (Table 1). These results are in agreement with Schumacher et al. (18), who found larger quantities of venom in European bee reservoirs (134.1±53.5µg) than in Africanized (98.2±35.9µg).

Venom quantity liberated in extraction apparatus (mg). The Africanized bees liberated larger quantities of venom in the extraction apparatus (0.0732±0.012 mg) than both the hybrids Carniolan (0.059±0.013 mg) and Italian (0.057±0.011 mg) (Table 2). A larger percentage of the reservoir volume was liberated by the Africanized than by the hybrids (Table 3).

Electro stimulus threshold to promote stinging (volts). The Africanized bees required a lower level of electro stimulus (volts) than the European hybrids (Table 4). The threshold to promote stinging was 10.75±1.37 volts for the Africanized, 15.01±1.63 volts for the Carniolan hybrids, and 15.11±2.00 volts for the Italian hybrids.

ACKNOWLEDGEMENTS

The authors are grateful to FAPESP and CNPq for the financial support.

Received 29 August 2000

Accepted 14 November 2000

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Publication Dates

• Publication in this collection
  08 Oct 2002
• Date of issue
  Dec 2001

History

• Accepted
  14 Nov 2000
• Received
  29 Aug 2000