Field Exploration for Colony Selection: Evaluating Hygienic Behavior in Apis cerana indica Colonies

Abstract

Hygienic behavior (HB) emerges as a pivotal trait, impacting colony resistance to diseases. This study aimed to understand the behavioral traits of Apis cerana indica colonies, with a focus on HB and other key characteristics crucial for colony health, and to screen and identify colonies with superior hygienic behavior and better performance to combat prevailing diseases and pests. This research spans a comprehensive field analysis with different seasons and locations, encompassing the distinct environmental and management factors that influence honey bee behavior. The inclusion of A. cerana indica colonies from various locations provides a novel perspective, offering valuable insights regarding the hygienic behavior of A. cerana indica. Several statistical analyses, including descriptive statistics, principal component analysis (PCA), and Aligned Rank Transformation-Analysis of Variance (ART-ANOVA) for repeated measures, shed light on the distribution of hive metrics, emphasizing the significance of considering seasonality and location-specific factors. PCA highlights unique characteristics in Tirupur and Coimbatore colonies, while correlation analyses uncover relationships among HB, honey, pollen, brood area, and adult population. Moreover, the study's nuanced findings gave the status of hygienic behavior of A. cerana indica colonies and identified colonies with better colony performance, which will be useful for future breeding programs with A. cerana indica.

Keywords: A. cerana indica; ART-ANOVA; colony metrics; honey; hygienic behavior; pollen.

Figure 1

Descriptive statistics of colony traits in (a) different seasons and (b) different locations.

Figure 2

PCA biplot showing colony clusters with traits as vectors.

Figure 3

Correlation analysis of colony traits (a) honey flow season and (b) dearth period. Note: L1—Tirupur, L2—Coimbatore, L3—Dindigul, L4—Madurai, L5—Kanyakumari, and L6—Erode. The significance levels are represented by ‘*’ (p < 0.05), ‘**’ (p < 0.01) and ‘***’ (p < 0.001).

Figure 4

Pairwise mean comparison among characters. The figure shows the average levels of five characters, (a) hygienic behavior, (b) honey area, (c) pollen area, (d) brood area, and (e) adult population, measured from six locations (Tirupur, Coimbatore, Dindigul, Madurai, Kanyakumari, and Erode) during two distinct periods (honey flow season and dearth period) using bar graphs. The average Cohen’s d effect size was used to quantify the difference between groups and is represented by alphabetic letters. Groups with the same alphabetic letter indicate that differences between those groups are not significant.

Figure 5

Effect sizes of main and interaction effects of parameters on different characters. The figure shows the relative importance of the main (season and location) effects and interaction (season × location) effects of the factors on five characters: (a) hygienic behavior, (b) honey area, (c) pollen area, (d) brood area, and (e) adult population, using doughnut diagrams.

Figure 6

Degree of performance of honey bee colonies. Cohen’s d statistic computed for pairwise mean comparison was summed across interactions and averaged to study the performance of colonies across six locations (Tirupur, Coimbatore, Dindigul, Madurai, Kanyakumari, and Erode) and two seasons (honey flow season and dearth period) measured by five different characters, (a) hygienic behavior, (b) honey area, (c) pollen area, (d) brood area, and (e) adult population, using a heat map. The color gradient from red to blue indicates the range of effect sizes from 1.0 to −1.0. The red color gradient indicates higher effect sizes, while the blue color gradient depicts the least effect sizes. White color represents non-significant effect sizes.

Figure 7

Hierarchical agglomerative clustering dendrogram for A. cerana indica colonies Note: In the Colony ID, the alphabet letters indicate the location (C—Coimbatore, D—Dindigul, E—Erode, K—Kanyakumari, M—Madurai, and T—Tirupur) and numbers represent corresponding colony number. For example, T4 is the colony no. 4 in Tirupur. The different colors represent different clusters (red—Cluster I, yellow—Cluster II, green—Cluster III, blue—Cluster IV, purple—Cluster V).