Responsiveness to inhibitory signals changes as a function of colony size in honeybees ( Apis mellifera )

Abstract

Biological collectives, like honeybee colonies, can make intelligent decisions and robustly adapt to changing conditions via intricate systems of excitatory and inhibitory signals. In this study, we explore the role of behavioural plasticity and its relationship to network size by manipulating honeybee colony exposure to an artificial inhibitory signal. As predicted, inhibition was strongest in large colonies and weakest in small colonies. This is ecologically relevant for honeybees, for which reduced inhibitory effects may increase robustness in small colonies that must maintain a minimum level of foraging and food stores. We discuss evidence for size-dependent plasticity in other types of biological networks.

Negative feedback may suppress variation to improve collective foraging performance

“…In agreement with field observations of honeybees, which increase stop signalling when a quick response is necessary [ 10 ], our analysis also predicts a speed-up of the group dynamics for higher levels of negative feedback. The dynamics of Fig 3 can also be discussed in light of the results of a recent empirical study which has found that sensitivity to inhibitory signalling changes as a function of colony size [ 34 ]. Our model, by linking the negative feedback rate with convergence speed and the deviation from the target distribution, offers predictions that can be tested on colonies of different sizes.…”

“…Our model, by linking the negative feedback rate with convergence speed and the deviation from the target distribution, offers predictions that can be tested on colonies of different sizes. For example, the time to adaptation to environmental changes is expected to be longer in smaller colonies, where bees show a lower sensitivity to inhibitory signalling [ 34 ], than in larger colonies.…”

“…Here we have shown that negative feedback may play an important role in reducing variance in colony foraging performance. For example, considering the honeybee system that inspired our model, field observations have reported that levels of stop signalling increase in response to changes such as dangerous, overcrowded, or depleted food patches [ 10 , 11 , 13 , 41 ]; however, it has not yet been fully understood why, even in static conditions, honeybees always deliver a small number of stop signals to foragers visiting the same forage patch [ 10 , 13 , 34 ]. This pattern is consistent with our model, and the analysis presented is an interpretation for such observed behaviour.…”

“…Finally, negative feedback evolved not only to respond better to changing environments, but also to reduce variance in foraging performance. The re-use of negative feedback signals, such as in the case of honeybee stop-signals which are used in both foraging [ 10 , 34 ] and house-hunting [ 22 ] life history stages, would facilitate performance-enhancing innovations in signalling behaviours; however, it is not clear whether stop-signalling first arose in foraging or in house-hunting contexts (intuitively, we suggest the former, a more common life history event).…”

Conditioned inhibition, inhibitory learning, response inhibition, and inhibitory control: Outlining a conceptual clarification.

“…Hornstein et al (2021) suggested that this may be explained by the fact that social support figures often do not prevent the occurrence of fearful incidents but instead they modulate the capacity to "cope" with emotional challenges. With regard to the origin of the features exhibited by social support cues, the authors propose that they are "prepared," which in this context means that they are acquired by means other than Pavlovian conditioning (for an example of a prepared inhibitory social signal in the appetitive domain, see Bell et al, 2021). Hornstein et al (2021) urged other researchers to pursue studies examining the route by which social support figures acquire fear suppression properties or assessing the possibility that those properties are innate.…”