CONICET | Buscador de Institutos y Recursos Humanos

Differences in habituation and dishabituation between pollen and nectar foragers contribute to foraging division of laborDivision of labor is central to the ecological success of social insects. Among foragers of the honeybee Apis mellifera (Hymenoptera: Apidae), specialization for collecting nectar or pollen correlates with sensitivity to sucrose. It has been shown that pollen foragers returning to the hive are more sensitive to sucrose than nectar foragers. Differences between nectar and pollen foragers have been also found in associative learning, with individuals performing better when rewarded with the stimuli to which they are more sensitive. Nevertheless, these differences havent been proved in non-associative learning. One of the most common non-associative learning processes is habituation, characterized by a graded decrease in a behavioral response as result of the repeated presentation of a stimulus. The habituated response can be dishabituated (recovered) by the same stimulus presented at a higher intensity or by an equivalent but different stimulus. Here, we hypothesized that pollen and nectar foragers differ in their habituation and dishabituation performance that we quantified by means of the proboscis extension reflex (PER), an innate response elicited when sucrose solution contacts the antennae. In our experiment,habituation trial consisted in the repeated presentation (25 events) of either: 1) sucrose-water solution (10% w/w) on the antenna or 2) sucrose-water solution (10% w/w) on the antenna plus hand-collected kiwi pollen on the first tarsi. Dishabituation was tested in bees habituated with sucrose-water solution (1) by means of repeated presentation (4 events) of sucrose-water solution (10%) on the antenna and pollen on the tarsi. Our results showed that habituation with sucrose-water solution was similar in pollen and nectar foragers. However, pollen foragers showed lower habituation (showing more frequent PER during habituation) than nectar foragers if trials included pollen as habituating stimulus. Moreover, dishabituation was higher in pollen than in nectar foragers. Taken together, our results suggest that both forager types perceive pollen differently, resulting in different performance during habituation and dishabituation. Our results support that the low habituation (and a high dishabituation) of pollen foragers to pollen stimulation contributes to foraging division of labor.

enviar mensaje