Stick Insect's Eggs Survive if Insect is Eaten by a Bird

Posted on April 5, 2019

Stick Insect Eggs Survive Bird Consumption

Scientists have discovered that the hardy eggs of a stick insect can survive being eaten by a bird. A team of Japanese researchers found that some eggs of the stick insect are excreted unharmed and are able to successfully hatch.

The research team was led by Associate Professor Kenji Suetsugu (Kobe University Graduate School of Science), Associate Professor Katsuro Ito (Kochi University), and Associate Professor Takeshi Yokoyama (Tokyo University of Agriculture and Technology). The findings were published in the online edition of Ecology.

The researchers say the process could help the stick insects expand their habitat just as plants use various methods to disperse seeds. The egg distribution method could potentially lead to a stick insect being born many miles from where its parent was consumed. The scientists say in the announcement, "If insect eggs can pass through birds unharmed, we could say that insects, just like plants, are using the birds as a means of long-distance transport."

The research team fed eggs from three species of stick insects to brown-eared bulbul. For all three species, between 5% and 20% of the eggs were excreted unharmed. The researchers also confirmed that for one species, eggs retrieved from the bird's excrement went on to successfully hatch.

Professor Suetsugu says, "Our next step is analyzing the genetic structure of stick insects. Based on this we'd like to investigate whether similar genetic structure of stick insects can be found along birds' migration flight paths, and whether there are genetic similarities between stick insects and plants that rely on birds for seed distribution". These investigations will reveal that the dispersal of stick insect eggs by birds could affect the distribution and gene flow of stick insects."

The image below shows the stick insect eggs collected from the excrement of brown-eared bulbul and a stick insect that hatched from one of the eggs.

Stick Insect Eggs Excreted by Bulbul

Image: Kobe University