Siblings’ rivalry could cause some mess in the house, however, wasps take this rivalry to a new level by cannibalizing their siblings in the absence of food.
A research team from the Kobe College, Japan, have determined this behavior is a species of wasps named "Isodontia harmandi", and announced their findings in the latest issue of the journal PLOS One.
This type of "solitary wasp" doesn't live communally in hives, but rather creates nurseries in naturally occurring plant cavities.
Females lay about a dozen eggs in the bodies of paralyzed insects that the larvae then consume upon hatching. After the babies hatch and gnaw through the insect corpses, an even more gruesome event unfolds: Some of the larvae begin devouring their siblings.
Between 2010 and 2015, researchers collected and analyzed over 300 I. harmandi nests, counting the number of eggs, larvae and cocoons to determine the size of the broods and then recording brood status during different developmental stages.
The researchers then reared larvae in 39 nests and found brood reduction in about 77% of the nests during larval stages and in about 59% of the nests after the cocoon stage.
The team found that the cannibals were typically bigger than the siblings that they ate and the victims were frequently newly-hatched or still very small and clinging to their insect prey.
"Female wasps lay too many eggs for all of the larvae to survive on the insect corpses that she provides, leaving her babies with no option but to cannibalize each other," study co-author Tomoji Endo, a professor emeritus in the School of Human Sciences at Kobe College in Japan, told the Live Science website.
"The researchers were surprised by how calmly they went about doing it, munching on their hapless victims without any obvious aggression," he explained.
In their next move, the researchers plan to study when and how wasp larvae realize that their original food supply is running low, and that sibling cannibalism is their best option for survival.
