Life in a Coconut Flower

An ascid mite, a relative of today's new species. Photo from Bee-Associated Mites of the World, licensed under CC BY 3.0.

An ascid mite, a relative of today’s new species. Photo from Bee-Associated Mites of the World, licensed under CC BY 3.0.

Mites are incredibly diverse — nearly 50,000 species have been described so far, but close to a million may await discovery. With most mites smaller than the head of a pin, studying them and describing new species can be a formidable challenge, requiring the use of powerful microscopes and, often, DNA sequencing.

Coupled with the diversity of species comes a tremendous diversity of lifestyles. Many (including ticks) are parasitic, living on the bodies of animals from insects to humans. Quite a few species are detritivores, eating decomposing leaf litter in the forest understory and helping to recycle nutrients so plants can grow. Others eat those plants, and some can be serious pests of agricultural crops.

There are also, of course, predatory mites, and some of these have proven quite useful to humans. Blattisocius tarsalis is one such mite (Nielsen 2003). In flour mills, tarsalis is used to control the Mediterranean flour moth (Ephestia kuehniella), whose caterpillars live, grow, and eat stored grains. Although the mites aren’t nearly large enough to prey on caterpillars or moths, they are effective predators of the moths’ eggs, which makes them highly effective. In recent years they have become more important as European governments have banned the use of certain pesticides in flour mills.

The Mediterranean flour moth. Photo by Sarefo, licensed under CC BY-SA 3.0.

The Mediterranean flour moth. Photo by Sarefo, licensed under CC BY-SA 3.0.

Living on an exclusive diet of moth eggs seems like an odd strategy, but not compared to the rest of the Blattisocius species. Although most are predators, at least one is a parasite that rides and feeds on adult moths (Halliday et al. 1998), and several, known as bee mites, live inside honey bee hives (Crozier 1989). What they do in there is not clear — although many mites can be found in bee hives, some are deadly parasites (like Varroa) while others are helpful cleaners by scavenging on detritus that collects in the hive.

Today’s new species, the coconut flower mite (Blattisocius thaicocofloris), may belong to any one (or several) of these categories. Scientists discovered the mite while studying the mite species associated with Thai coconut plantations, where some mites are pests but others, by eating those pests, are beneficial (Oliviera et al. 2015). The new species was found inside the flowers of coconut trees, so it might be preying on mites or insect eggs on the plant.

Coconut trees and their flowers are home to a dizzying array of species. Can you spot two geckos? Photo by Muhammad Mahdi Karim, licensed under GFDL-1.2.

Coconut trees and their flowers are home to a dizzying array of species. Can you spot two geckos? Photo by Muhammad Mahdi Karim, licensed under GFDL-1.2.

The mite’s discoverers aren’t so sure, however. Coconut flowers are often visited by honey bees, so they suggest that the flower mite could be a bee associate, living in hives and riding bees to and from flowers. This might like a stretch of the imagination, but many species of honey bee hive “squatters” (including a pseudoscorpion: Subbiah et al. 1957) have been observed doing the same thing. Understanding the relationship between these mites and bees may be important — although coconut tree pollen can travel by wind, bees are important to make sure as many flowers as possible become pollinated and develop into coconuts.

Whether they prowl coconut trees for insect egg prey, take joy rides on the backs of honey bees, or do something else that biologists couldn’t possibly think of, the coconut flower mite is just one of many mites about which we know far too little.

To learn more about mites that live in and around bee hives, be sure to check out the North American Bee Mite project at their website. Here you can read about all sorts of bee-associate mites, from parasites to scavengers and everything in between. The project is funded by the U.S. Department of Agriculture, and the website maintained by Dr. Barry O’Connor and Dr. Pavel Klimov of the University of Michigan.

Cited:

Crozier L. 1989. Melittiphis alvearius (Berlese) and other mites found in honeybee colonies in Nova Scotia. Journal of Apicultural Research 28: 166-168.

Halliday R.B., D.E. Walter, and E.E. Lindquist. 1998. Revision of the Australian Ascidae (Acarina : Mesostigmata). Invertebrate Taxonomy 12: 1-54.

Nielsen P.S. 2003. Predation by Blattisocius tarsalis (Berlese) (Acari: Ascidae) on eggs of Ephestia kuehniella Zeller (Lepidoptera: Pyralidae). Journal of Stored Products Research 39(4): 395-400.

Oliviera D.C., A. Chandrapatya, and G.J. de Morales. 2015. A new species of Blattisocius (Acari: Mesostigmata: Blattisociidae), with a new characterisation of the genus. Zootaxa 4040(1): 93–100.

Subbiah M.S., V. Mahadevan, and R. Janakiraman. 1957. A note on the occurrence of an arachnid – Ellingsenius indicus Chamberlin – infesting bee hives in South India. Indian Journal of Veterinary Science and Animal Husbandry 27: 155-156.

 

 

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