Posts Tagged 'Apis'

Negative feedback signal in a superorganism

It has long been understood that worker honey bees, Apis mellifera, coordinate foraging for nectar using a system for dances. The best understood of these dances is the ‘waggle dance’. The waggle dance is preformed by a worker who has recently returned to the hive from a lucrative nectar source. The bee gives off an olfactory cue that tells her hive-mates to pay attention. The worker then begins to move in a rough figure-eight, vibrating her abdomen at high frequencies between the loops. The angle and duration of the vibration convey the direction and distance to a promising nectar source.

Check out this video about the waggle dance:

Honey bees also preform a tremble dance that lets workers know that a nectar-laden forager needs to be offloaded, and another dance, originally though of as a ‘begging dance’. This dance is preformed by workers that approach waggle dancers and either butt heads or climb on top of the waggler before delivering a brief 380 Hz abdominal vibration. It was originally thought that this dance was a way of begging for nectar from a laden dancer. However, research has shown that this dance does not precipitate nectar exchange.

New research has shown that the begging dance is in reality a ‘stop dance’, that tells a waggler to stop sending others to a perilous location. The research, published in Current Biology, showed that the stop dance is caused by predator and conspecific attacks on foragers. Workers returning from this dangerous location seek out waggle dancers that are sending others into danger. The stop dance decreases waggle dancing and recruitment to that location.

This stop dance is especially interesting when considered within the superorganism concept of eusocial insects. In this view, the entire colony functions as a single organism; with different colony classes acting as different cell types, and individuals analogous to single cellular units. Previously, only positive recruitment signals had been modeled at the superorganism level. Now, the stop dance adds the first example of a negative feedback signal in a superorganism. The collective interplay of waggle and stop dancing by many members of a hive therefore results in a self-organizing labor allocation system similar to those that exist at the cellular level.

References:

    Nieh, J. (2010). A Negative Feedback Signal That Is Triggered by Peril Curbs Honey Bee Recruitment Current Biology, 20 (4), 310-315 DOI: 10.1016/j.cub.2009.12.060

Bees can learn to discriminate human faces

New research published in the Journal of Experimental Biology sheds light onto visual stimuli processing in arthropods. Researchers (Avargues-Weber et al., 2010) have shown that honeybees, Apis mellifera, are capable of complex visual processing and learning tasks that are commonly reserved for primates. With a small fraction of mammalian neural complexity, honeybees are capable of discriminating face-like visual stimuli; both between face-like and non-face-like stimuli and between variations of face like stimuli. That is, the honeybees are capable of visually discriminating and remembering one human face from another.

Of course, there is no ecological reasoning for honeybees to discriminate human faces, but the behavior is a clue about the bee’s underlying visual processing capacities. This research tells us that honeybees are able to perceive and learn, not just the individual components of a visual stimulus, but the interrelationships between them. This is the first demonstrated instance of configural processing in an arthropod.

Members of this research team first suggested that bees were capable of discriminating human faces in 2005. However, their work was criticized because it did not control for low-level stimuli (individual cues, center of gravity, symmetry, spacial frequency, and background cues) in the faces. That is, the researchers did not clearly show that the bees were actually carrying out configural processing; perceiving the interrelationships of multiple facial components processed together.

In their new paper, the researchers preformed a variety of behavioral experiments to control for low-level visual cues. They primarily used a Y-maze chamber with a choice of two visual stimuli at the end of the two branches. The bees were trained to associate a sugar reward with one of the stimuli. Afterwords, in the absence of a reward, the researchers recorded the percentage of correct choices by the bees.

First, the researchers showed that the bees could distinguish face-like and non-face-like arrangements of dashes and dots. Furthermore, they confirmed that the bees were discriminating based on the combined relationship of the eyes, nose, and mouth components of the face-like arrangements; and not just the orientation of individual components. A series of additional controls showed that the bees were not using symmetry, center of gravity, or spatial frequency cues to distinguish the stimuli. Finally, the researchers showed that the honeybees could also distinguish photos of human faces.
Some of the choices that the honeybees were able to distinguish.

This research concludes that honeybees are capable of high-level cue integration and configural visual processing. Such a capacity in honeybees is likely used for navigation and identifying flowers. The neurobiology responsible for configural visual processing is only partially understood in humans, and completely undescribed in arthropods. By working out this processing system in comparatively simple insect brains, researchers can hope to eventually apply this finding to synthetic facial recognition systems.

References:

  • Avargues-Weber, A., Portelli, G., Benard, J., Dyer, A., & Giurfa, M. (2010). Configural processing enables discrimination and categorization of face-like stimuli in honeybees Journal of Experimental Biology, 213 (4), 593-601 DOI: 10.1242/jeb.039263
  • Dyer, A.G., Neumeyer, C. & Chittka, L., 2005. Honeybee (Apis mellifera) vision can discriminate between and recognise images of human faces. J Exp Biol, 208(24), 4709-4714.



I have moved.
Arthropoda can now be found here.

Michael Bok is a graduate student studying the visual system of mantis shrimp.

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Johanneksenkirkko with a firey sunset.

Frozen Gulf of Finland

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Nudibranch from Lizard Island

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Bringing in the catch

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