In insects, nitrogenous waste excretion is managed by the Malpighian tubules – a series of long, meandering tubes that collect waste products from the hemolymph to be excreted with digestive waste via the rectum. Malpighian tubules are broadly equivalent in function to the vertebrate kidney.
Figure 3.13 Digestive system.
Source: Illustration by Patrick D. Wilson.
The function of the vertebrate liver is provided in insects by the “fat bodies.” Fat bodies are small organs that lie on the dorsal and ventral aspects of the abdomen and play a critical role in the synthesis of hemolymph proteins and the synthesis and storage of lipids. The fat bodies are critical for the survival and successful overwintering of honey bees. It was recently reported that the Varroa mite, which can so devastate hives, feeds not on hemolymph but on the fat bodies of infested bees (Ramsey et al. 2019).
Glands
Bees possess numerous specialty glands that secrete substances necessary for feeding larvae, defending the hive, building comb, recognizing the home hive, and functions (Bortolotti and Costa 2014). The glands illustrated in Figures 3.14 and 3.15 are more fully described in Chapter 4 – Physiology.
Reproductive System
The drone possesses the apparatus necessary for insemination of the queen – large eyes to spot a queen, excellent flying skills, and an endophallus. Spermatozoa are transferred to the queen with the endophallus, which breaks from the drone. The mating process kills the drone (Vidal‐Naquet 2015).
Figure 3.14 Overview of the glands of the honey bee. The presence or absence of particular glands at any given time in the individual's life depends on the age/caste of the worker (nurse bee, forager, etc.) versus a queen or a drone (Vidal‐Naquet 2015).
Source: Illustration by Patrick D. Wilson.
Figure 3.15 Wax scales emerging from the wax glands.
Source: Photo courtesy of Zachary Y. Huang.
Figure 3.16 Ovary of a laying queen. Individual ovarioles can be observed with eggs.
Source: Photo courtesy of Zachary Y. Huang.
The queen receives spermatozoa from multiple drones and stores it within a spermatotheca. The spermatotheca releases sperm into the vagina to fertilize the egg as it passes (Vidal‐Naquet 2015) (Figure 3.16).
More detailed information and descriptions of honey bee anatomy can be found in the references.
References
1 Avarguès‐Weber, A., Mota, T., and Giurfa, M. (2012). New vistas on honey bee vision. Apidologie 43: 244–268.
2 Bortolotti L, Costa C. Chemical Communication in the Honey Bee Society. In: Mucignat‐Caretta C, editor. Neurobiology of Chemical Communication. Boca Raton (FL): CRC Press/Taylor & Francis; 2014. Chapter 5. Available from: https://www.ncbi.nlm.nih.gov/books/NBK200983/
3 Kelber, A., Vorobyev, M., and Osorio, D. (2003). Animal color vision – behavioral tests and physiological concepts. Biological Reviews 78: 81–118.
4 Ramsey, S.D., Ochoa, R., Bauchan, G. et al. (2019). Varroa destructor feeds primarily on honey bee fat body tissue and not hemolymph. Proceedings of the National Academy of Sciences of the United States of America 116: 1792–1801.
5 Snodgrass, R.E., Erickson, E.H., and Fahrbach, S.E. (2015). The Hive and the Honey Bee. Hamilton, IL: Dadant and Son.
6 Vidal‐Naquet, N. (2015). Honeybee Veterinary Medicine: Apis Mellifera L. Sheffield, UK: 5M.
4 Physiology of the Honey Bee – Principles for the Beekeeper and Veterinarian
Rolfe M. Radcliffe
Large Animal Surgery and Emergency Critical Care, College of Veterinary Medicine, Cornell University, Ithaca, NY, USA
* Illustrations by Lauren D. Sawchyn
Both beekeepers and veterinarians working with bees require an understanding of the honey bee individual and superorganism. It is imperative to be able to identify what is normal biology – anatomy, function, and behavior – for the individual honey bee and its colony and what is abnormal or unhealthy, to provide the appropriate management steps to control or eliminate a problem or disease. For example, understanding honey bee physiology and communication will provide the basis for making informed decisions about diseases like varroa mite that may affect many different features (e.g. bee weight, lifespan and bee numbers, deformities, behavior, reproduction) of a honey bee and their collective hive functions. Further, a full understanding of honey bee biology will help the beekeeper and veterinarian achieve their goal(s), whether it be for the production of honey, beeswax, pollination or other services.
The honey bee and its collective colony is a marvel of nature. The following passage from The Superorganism: the beauty, elegance and strangeness of insect societies, by Hölldobler and Wilson (2009), eloquently summaries the complexity of such a life:
Consider a honey bee gathering nectar from a flower bed. Although simple in appearance, the act is a performance of high virtuosity. The forager was guided to this spot by dances of her nestmates that contained symbolic information about the direction, distance, and quality of the nectar source. To reach her destination, she traveled the equivalent of hundreds of human miles at bee‐equivalent supersonic speed. She has arrived at an hour when the flowers are most likely to be richly productive. Now she closely inspects the willing blossoms by touch and smell and extracts the nectar with intricate movements of her legs and proboscis. Then she flies home in a straight line. All this she accomplishes with a brain the size of a grain of sand and with little or no prior experience.
Part 1: Comparing Vertebrates and Bees
Physiology