Cannibalistic spiders refrain from hunting their kin alive, yet promptly consume their deceased brethren.
In a groundbreaking study conducted in southwest France, researchers Lempereur and Jeanson have discovered a fascinating behavioural shift in the labyrinth spider (Agelena labyrinthica). The study, which involved collecting and hatching labyrinth spider egg sacs in a lab, has shed light on how these cannibalistic spiders, known for their intricate tunnel systems or labyrinths, manage their social dynamics.
The research has revealed that young labyrinth spiderlings, content to share a web with their siblings at a young age, remain civil even when deprived of food. This behaviour, it seems, is not solely driven by the lack of food but is influenced by the spiders' social environment.
Remarkably, these young spiderlings initially live off egg yolk from the eggs they're born in, but can catch flies within days of hatching. However, the study found that labyrinth spiders, when living siblings die, consume them within an hour. Yet, this behaviour does not occur with dead siblings.
As the spiderlings grow older, they appear to shift from active cannibalism to opportunistic scavenging. This shift likely reflects an adaptive balance between avoiding harmful cannibalism early on and optimising nutrient intake through scavenging when older. Young spiders avoid harming live siblings to maintain kin, while older spiders consume corpses to gain energy without direct lethal combat.
The study also suggests that a spider living alone has no reason to respond to cues emitted by other spiders, except during reproduction. Living labyrinth spiders may send a "life signal" to one another through chemicals, which is one of the ways spiders communicate, according to the study. However, social isolation reduces sensitivity to social signals in labyrinth spiders.
The spiderlings raised in groups of four were significantly less aggressive to one another than the spiders raised alone. This finding indicates that the social signals do prevent cannibalism among living siblings, but these signals do not prevent cannibalism of dead siblings.
The researchers will now investigate the makeup of the "life signal" that living labyrinth spiders send to one another. This study provides valuable insights into the complex social behaviour of labyrinth spiders and offers a deeper understanding of the intricate balance between cooperation and competition in these fascinating creatures.
The study's findings in labyrinth spiders also spark curiosity about the role of social dynamics in other fields, such as health-and-wellness and mental-health. For instance, understanding how these spiders manage their social environment could shed light on human behavioral patterns. Moreover, studying the shift in behavior from cannibalism to scavenging can be paralleled with the importance of nutritional choices for maintaining physical health and fitness-and-exercise. Lastly, the concept of "life signals" among labyrinth spiders could have implications in the domain of space-and-astronomy, where communicating over vast distances relies on similar mechanisms to maintain contact and cooperation.
