by Piter Kehoma Boll
Last week I introduced the Cuban Laurel Thrips, which feeds on several fig trees, such as the Chinese Banyan and the Cuban Laurel. Today, we will continue up the food chain and talk about a mite that is a parasite of the cuban laurel thrips. Named Adactylidium gynaikothripsi, I decided to give it the common name “Cuban-Laurel-Thrips Mite”.
The Cuban-laurel-thrips mite was described only in 2011 from Cuban laurel thrips populations in Greece. This is the fourth mite of the genus Adactylidium known to parasitize the Cuban laurel thrips, the other four being Adactylidium ficorum (“fig-thrips mite”), A. brasiliensis (“Brazilian thrips mite”) and A. fletchmani (“Fletchman’s thrips mite”). As you can imagine, in order to parasitize an insect as small as the Cuban laurel thrips, these mites are even smaller, measuring about 0.1 mm in length.
The life cycle of the Cuban-laurel-thrips mite, which is basically the same for all species of Adactylidium, is very bizarre. Adult females feed on the eggs of the Cuban Laurel Thrips. They start their adult life wandering over fig leaves looking for a suitable thrips egg to attack. Once finding one, they pierce the egg’s shell with their chelicerae and attach to it like ticks and start to eat. They feed on a single egg across their entire life. If they are unable to find an egg, they may also attach to an adult thrips as a last resource, or else they die of starvation in a few hours.
Once a female starts to eat, a small group of eggs, usually between 5 to 10, begins to develop inside her. The eggs grow during the first 48 hours after the female attached to the egg, making her double in size and becoming something like a spherical egg sac. The eggs hatch around this time and the mite larvae remain inside their mother. These larvae lack mouth parts, so it is believed that they absorb nutrients from her mother directly through the body surface. About 24 hours later, the larvae turn into nymphs, which remain inactive inside the shed skin of the larva. They also lack any mouth parts.
Another 24 hours pass and the nymphs turn into adult mites. They are still inside their mother when this happens. The adults consist always of a single male and several females. This male then starts to copulate with his own sisters, still inside their mother’s abdomen, and, when copulation is finished, they start to tear their mother’s body apart to get free, killing her in the process. Once outside the body, the male dies in a few minutes, never eating anything other than his own mother. The females, on the other hand, start to look for thrips eggs on which to feed, only to be killed by her own children less than 4 days laters.
This entire life cycle may look very insane from our human perspective, but nature was never interested in following our moral rules.
– – –
– – –
Antonatos SA, Kapaxidi EV, Papadoulis, GT (2011) Adactylidium gynaikothripsi n. sp. (Acari: Acarophenacidae) associated with Gynaikothrips ficorum (Marshal) (Thysanoptera: Phlaeothripidae) from Greece. International Journal of Acarology, 37(sup1), 18–26. doi: 10.1080/01647954.2010.531763
Elbadry, EA, Tawfik, MSF (1966) Life Cycle of the Mite Adactylidium sp. (Acarina: Pyemotidae), a Predator of Thrips Eggs in the United Arab Republic. Annals of the Entomological Society of America, 59(3), 458–461. doi: 10.1093/aesa/59.3.458