The significance of Apis cerana cerana (Hymenoptera: Apidae) gnawing off the old brood cells

Abstract

Apis cerana cerana has the biological characteristic of gnawing off the old brood cells which reared multiple generations of workers. This study investigated the internal structure of newly built, old, and semi-rebuilt brood cells and their effects on the morphological development of workers to understand the significance of Apis cerana cerana gnawing off the old brood cells. The results showed that there was no significant difference among the three diameters (at the top, middle, and bottom positions) of newly built or semi-rebuilt brood cells (P > 0.05), but these changed within the old brood cells (P < 0.05). The top, middle, or bottom diameters of the newly built and semi-rebuilt brood cells were significantly larger than those of the old brood cells (P < 0.05), but were almost the same between the newly built and the semi-rebuilt brood cells (P > 0.05). The weight and base thickness of the cocoon were significantly greater in the old brood cells than those in the semi-rebuilt brood cells (P < 0.05). Importantly, the birth weight, body length, and the tested six external morphological indices did not show a significant difference between the newly built and semi-rebuilt brood cells (P > 0.05) but were significantly larger than those of old brood cells (P < 0.05). The size of the brood cell and the external morphology of the workers showed a positive correlation. This study highlights the significance of Apis cerana cerana gnawing off the old brood cells providing a reference for its scientific rearing.

Analysis of comb-gnawing behavior in Apis cerana cerana (Hymenoptera: Apidae)

“…A study examining the brood cell structure of Western honey bees ( A. mellifera ) reported that workers expand the volume of brood cells by carefully cleaning the accumulated debris within the cells and secreting wax to increase the cell wall height, which helps the normal development of broods ( Таранов 1961 ). In contrast, A. c. cerana has evolved biological traits to gnaw away old combs, balancing the negative impact of old brood cells on the colony ( Meng et al 2023 ). In this study, we observed that age is one of the major factors contributing to the comb-gnawing behavior.…”

“…Esters and hydrocarbons are the primary components of beeswax that can absorb dark pigments that are produced from the brood’s secretions, turning the comb color brown or black, and the comb color intensity is typically associated with its age ( Tulloch 1980 , Berry and Delaplane 2001 ). After multiple generations of worker rearing, a brood cell becomes reduced in size due to the accumulation of cocoons and other materials ( Hepburn et al 2007 , Meng et al 2023 ). The reduced size of brood cells negatively impacts the morphological characteristics of workers ( Alfalah et al 2012 ).…”

Impact of Brood Cell Cocoons on Metal Accumulation and CYP450 Detoxification Gene Expression in Apis cerana cerana

“…Initially, two types of experimental combs were collected. These included three single-generation combs that had reared one generation of workers and three multi-generation combs that had reared numerous generations of workers (approximately eight generations), with a 1-year age and with some brood cells gnawed by workers [ 11 , 39 ]. Then, a 50 cm 2 comb block was cut from each comb’s brood-rearing area using an uncapping knife.…”

“…Specifically, old combs produce a positive feedback regulation that leads to several negative effects on the colony [ 8 , 9 ]. Compared to newly built or fresh combs, the structure of old brood cells is altered, leading to a volume reduction of about 9% [ 10 , 11 ]. This results in workers with lighter birth weights and reduced external morphometric sizes [ 12 ].…”

“…The cocoon, composed of honey bee silk secreted during the spinning larval stage, adheres to the cell wall along with feces and other secretions [ 16 ]. With the habit of reusing cells for brood-rearing, the layers and quality of the accumulated cocoon increase with each new worker’s generation [ 11 ]. Thus, the temporal (through multiple generations) and spatial (occupy cell volume) accumulation characteristics of cocoons in the brood cells may have the potential to continuously accumulate harmful substances such as heavy metals.…”