scholarly journals Possible interference of Bacillus thuringiensis in the survival and behavior of Africanized honey bees (Apis mellifera)

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Gabriela Libardoni ◽  
Pedro Manuel Oliveira Janeiro Neves ◽  
Raiza Abati ◽  
Amanda Roberta Sampaio ◽  
Fabiana Martins Costa-Maia ◽  
...  

AbstractBacillus thuringiensis (Bt), an entomopathogenic bacterium, has been used as bioinsecticides for insect pest control worldwide. Consequently, the objective of this work was to evaluate the possible effects of commercial formulations of Bt products, Dipel and Xentari, on the survival and behavior of Africanized honey bees (Apis mellifera). Bioassays were performed on foragers and newly emerged (24-h-old) bees that received the products mixed in the food. Their survival and behavior were evaluated through the vertical displacement tests and the walk test, analyzed using software Bee-Move. Then, histological analysis of the mesenterium was performed. As control treatment was used sterile water. The honey bees’ survival was evaluated for between 1 and 144 h. No interference of B. thuringiensis, Dipel and Xentari, in the survival of Africanized honey bees were found. Only Xentari interfered with vertical displacement behavior of newly emerged (24-h-old) bees. Both the products tested were selective and safe for A. mellifera.

Horticulturae ◽  
2021 ◽  
Vol 7 (4) ◽  
pp. 62
Author(s):  
Tae-Kwon Son ◽  
Md Munir Mostafiz ◽  
Hwal-Su Hwang ◽  
Nguyen Truong Thạnh ◽  
Kyeong-Yeoll Lee

In various orchard fruit trees, thinning of blossoms and fruits is important to increase fruit size and quality and to promote a new bloom in the following season. Several chemical thinning agents are currently commercially available, but they are inconsistent and produce side effects in crop plants and insect pollinators. Because of environmental concerns, developing alternative eco-friendly bloom thinning agents is necessary. We developed an eco-friendly bloom thinning formulation (BTF) using minerals and extracts of various medicinal plants. Our BTF spray (0.1%, <i>w/v</i>) decreased the number of fruits per tree (46.5%) and fruit yield per tree (81.5%) but increased the fruit weight (196.8%) compared with the control treatment; the spray induced a small number of larger mango fruits in the treated trees. We also investigated the effect of BTF on the olfactory behavior of <i>Apis mellifera</i> L. (Hymenoptera, Apidae), a major insect pollinator. We analyzed the behavioral changes of adult workers at two different concentrations (0.1% and 1%) of nine different BTF spray components using a Y-tube olfactometer. The behavioral responses of honey bees to nine BTF components showed significant differences. However, honey bees showed no clear attraction or repellent behavior towards the tested BTF components. Our results suggest that the newly developed eco-friendly BTF is practically applicable in mango orchards without interrupting honey bee behavior.


Author(s):  
Vagner de Alencar Arnaut de Toledo ◽  
Regina Helena Nogueira-Couto

This experiment was carried out to study the internal temperature regulation of a colony of Africanized honey bees (AFR), compared with hybrid Caucasian (CAU), Italian (ITA), and Carniolan (CAR) bees, during the period of one year and different size hives located in a sub-tropical region. The instant internal temperature, 33.7 ± 1.5° C for the AFR, 33.5 ± 1.4° C for the CAU, 33.7 ± 1.5° C for the ITA and 33.8 ± 1.4° C for the CAR, did not show any significant difference (P>0.05). The maximum temperature (36.1 ± 2.3° C) was statistically different (P<0.05) from the minimum (27.6 ± 5.3° C). There was no difference (P>0.05) in the mean internal temperature, between the nucleus (31.7 ± 6.3° C) and the brood nest (32.1 ± 5.3° C) measured between two and four o'clock in the afternoon.


1999 ◽  
Vol 22 (3) ◽  
pp. 321-323 ◽  
Author(s):  
Geraldo Moretto ◽  
Leonidas João de Mello Jr.

Different levels of infestation with the mite Varroa jacobsoni have been observed in the various Apis mellifera races. In general, bees of European races are more susceptible to the mite than African honey bees and their hybrids. In Brazil honey bee colonies are not treated against the mite, though apparently both climate and bee race influence the mite infestation. Six mixed colonies were made with Italian and Africanized honey bees. The percentage infestation by this parasite was found to be significantly lower in adult Africanized (1.69 ± 0.44) than Italian bees (2.79 ± 0.65). This ratio was similar to that found in Mexico, even though the Africanized bees tested there had not been in contact with varroa, compared to more than 20 years of the coexistence in Brazil. However, mean mite infestation in Brazil on both kinds of bees was only about a third of that found in Mexico.


2004 ◽  
Vol 94 (3_suppl) ◽  
pp. 1107-1115 ◽  
Author(s):  
Charles I. Abramson ◽  
Aaron J. Place ◽  
Italo S. Aquino ◽  
Andrea Fernandez

Experiments were designed to determine whether ethanol influenced aggression in honey bees. Two experiments are reported. In Exp. 1, harnessed honey bees were fed a 1%, 5%, 10%, or 20% ethanol solution. Two control groups received either a sucrose solution only or no pretreatment, respectively. The dependent variable was the number of sting extensions over 10 min. Analysis showed that aggression in harnessed bees was not influenced by prior ethanol consumption. Because there was some suspicion that the extension of the sting apparatus may be hindered by harnessing, and the authors wanted to use a design that increased ecological validity, Exp. 2 was conducted with free-flying bees. Sucrose or 20% ethanol solutions were placed in front of beehives, and the number of stings on a leather patch dangled in front of the hive served as the dependent variable. The experiment was terminated after 5 hr. because bees exposed to ethanol became dangerously aggressive. A unique aspect of the study was that Africanized honey bees were used.


2018 ◽  
Vol 39 (1) ◽  
pp. 329 ◽  
Author(s):  
Gabriela Libardoni ◽  
Alfredo De Gouvea ◽  
Fabiana Martins Costa-Maia ◽  
Everton Ricardi Lozano ◽  
Patrícia Franchi de Freitas ◽  
...  

The aim of this study was to assess the effects of three strains of Bacillus thuringiensis (Bt) on the longevity of workers of Africanized honey bee. Solutions at a concentration of 3 × 108 spores.mL-1 (dosage) were prepared for each strain of Bt (IPS 82, BR 81, and BR 147). Three bioassays were performed as follows: spraying on the bees, contact with the sprayed surface, and candy paste incorporated with Bt. The bees of the Bt bioassay were submitted to histological analysis of the mesenteron. The longevity of workers was assessed from one to 120 hours using different ranges. It was found that the bees that were exposed to the strain of Bt IPS 82, in the spraying test, exhibited a reduced longevity. In the contact test, the BR 147 strain reduced the longevity of the bees. In the food test, in turn, the three studied strains reduced the longevity of the bees as follows: Bt IPS 82: 64.5 hours; Bt BR 81: 64.5 hours; and Bt BR 147: 60.0 hours. The Bt BR 81 strain was considered the most selective of the evaluated strains on Apis mellifera, reducing the longevity of this bee only when it came into contact by the method of ingestion.


Apidologie ◽  
2008 ◽  
Vol 39 (5) ◽  
pp. 523-530 ◽  
Author(s):  
Oscar Zárate ◽  
Chavier De Araujo-Freitas ◽  
Luis A. Medina ◽  
Alfonso Velásquez ◽  
J. Javier G. Quezada-Euán

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