Camouflage feeding: leaf bite patterns are proportional to beetle body size

Authors: JING REN - Chinese Academy Of Sciences; DE GUNTEN, NATASHA - Georgia Institute Of Technology; Konstantinov, Alexander - Alex; HU, DAVID - Georgia Institute Of Technology; SI-QINGE - Chinese Academy Of Agricultural Sciences

Submitted to: Zootaxa
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/30/2017
Publication Date: 6/11/2018
Citation: Jing Ren, De Gunten, N., Konstantinov, A.S., Hu, D., Si-Qinge 2018. Camouflage feeding: leaf bite patterns are proportional to beetle body size. Zootaxa. 35:199-207.

Interpretive Summary: Leaf beetles, especially flea beetles, are among the most important insects for U.S. agriculture. Many are serious pests and feed on crops destroying valuable plants costing millions of dollars annually. Others are important biological control agents that can be used to control unwanted and invasive weeds. This paper focuses on how the leaf beetles protect themselves by an active camouflage external feeding pattern. This study will be useful to biological control workers, taxonomists, ecologists, and anyone interested in plant feeding beetles.

Technical Abstract: Feeding is an essential component of an insect’s behavioral repertoire and forms a mechanistic link between physiology and behavior [1, 2]. The most extensive studies of insect feeding mainly focus on the relationships between insect and plant, like plant damaged-self recognition [3-6], plant defensive strategies against herbivorous insects [7-9], or insects repressing plant immune responses [10]. However, studies about how the insects protect themselves when they feeding, especially for those feeding externally on plants, are very scarce. This paper focuses on how the leaf beetles protect themselves by an active camouflage external feeding pattern. To prove this, we measured the hole dimensions of 35 individual leaf beetles and performed time-lapse photography of feeding and micro-CT scanning of the foregut on a specific leaf beetle, Altica cirsicola. The results concluded that feeding holes are proportional to leaf beetle body size and hole dimensions of leaf beetle are constrained by two factors: foregut volume and head-prothorax mobility. We created a computer program to show that hole feeding is an active form of camouflage: they camouflage using both the number of size of their feeding holes. The measurements from human observers showed that the more holes and the hole size closer to the body size, the better to camouflage the leaf beetles themselves. In this study, we found a new and interesting camouflage behavior and provided a new sight on the studies of insect camouflage. This master camouflage behavior is also helpful to understand why insects are the most prosperous animals in evolution.