23 de setembre 2014

QUÈ PROVOCA L'AGRESSIVITAT DE LES ABELLES?

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Moltes vegades els apicultors ens preguntem què provoca l'agressivitat de les abelles, sobretot quan una colònia dòcil es transforma i un núvol d'abelles ataquen l'apicultor.

Molts aspectes fisiològics d'una colònia d'abelles són de naturalesa cíclica, i l'agressió no n'és pas l'excepció. Les abelles tenen la capacitat de ser agressives en qualsevol moment, però certs factors n'afavoreixen la seva manifestació, sobretot a finals de l'estiu i principis de la tardor. Alguns d'aquests factors són:

  • La manca de reina pot ser causa d'un increment de l'agressivitat
  • La falta d'una bona floració, fet que genera pillatge
  • Una alimentació artificial massa lenta, fet que provoca obrir les arnes massa temps i l'olor a xarop pot excitar perillosament les abelles.
  • La proximitat d'un tempesta o canvi de temperatura.  
Rusty

Article original


You’ve managed your honey bee colonies all spring and summer with no problem. Now and then an aggressive guard warned you off, but in general the bees were docile.
All of a sudden, however, the bees are angry. They fly at you. They form a dark cloud above their hive. They bury themselves in your pet’s fur. What gives?
Many aspects of a honey bee colony are cyclic in nature, and aggression is no exception. Honey bees have the ability to be aggressive at any time, but certain things set them off. In the late summer and early fall, more of these conditions exist.
Here are some of the factors that make for aggressive honey bees:
  • Queenlessness is frequently a cause of feisty bees. The bad behavior usually stops as soon as the colony or the beekeeper replaces the queen.
  • A shortage of nectar-producing flowers is called a nectar dearth. The bees can’t find nectar so they often try to steal it from other hives. This begins an aggressive behavior known as robbing.
  • Not only are robbing bees aggressive, but the bees being robbed become aggressive defenders of their stores. This often results in a cloud of bees around a hive, especially in the fall.
  • Look carefully. If robbing is going on, you will see bees fighting with each other at the hive entrance. The ground in front of the hive may be littered with dead honey bees.
  • The fighting bees release an alarm pheromone—an odor that warns other bees of the danger. The alarm pheromone makes other honey bees aggressive—more fighting means more pheromone is released which means more bees join the fray. The situation can escalate quickly.
  • Once the alarm pheromone has aroused the bees, you and your pets and your neighbors are fair game as well.
  • The odor of dead bees and the scent of honey being robbed attract other predators. Before long, wasps and yellow jackets have arrived on the scene to collect both meat and honey. This means more fighting and more alarm pheromone. What a mess.
  • Honey bees and wasps are not the only creatures preparing for winter. Colonies in the fall may be attacked by raccoons, opossums, or skunks. Regular visits by any creature—including a beekeeper—may make honey bees more aggressive.
  • Rainy weather, especially when it comes with heat and high humidity, makes bees cranky as well. During the “dog days of summer” no amount of fanning helps evaporate the nectar or cool the hive.
Of course, other factors can produce an aggressive hive. If the queen was superseded by a queen with more aggressive or Africanized genes, that could be the source of the problem. This is unlikely, however. More often than not aggressive behavior is merely a part of the cyclic nature of honey bee colonies.

Rusty

Font: honeybeesuite.com