by Piter Kehoma Boll
Last week I presented the magnificent Chinese banyan Ficus microcarpa. Today I’m bringing a little insect that loves it but is not loved in return, the Cuban laurel thrips, Gynaikothrips ficorum.
As its name suggests, the Cuban laurel thrips is a thrips, i.e., an insect of the order Thysanoptera. Adults of this species measure about 3 mm in length and have a black and elongate body and two pairs of thin wings that fold over the dorsum when at rest. Its mouth parts, as typical of thrips, are asymmetrical, with a reduced right mandible and a developed left mandible that it uses to cut the surface of plants in order to suck its juices. It is, therefore, a plant pest.
The Cuban laurel thrips prefers to feed on juices of fig trees, such as the Chinese banyan from last week. It’s common name, though, is a reference to another fig species, Ficus retusa, commonly known as the Cuban laurel. Both fig trees, as well as the thrips itself, are native from Southeast Asia. Other, less common host plants include Citrus trees and orchids. They prefer to feed on young, tender leaves, and cause dark, usually purplish red dots, on the leaf’s surface. It is common for the leaf to curl and become hard, eventually dying prematurely. Although most infestations do not cause serious damage to the plant’s development, the curling of the leaves can reduce a plant’s ornamental value.
The reproduction of the Cuban laurel thrips is basically constant, so that several generations occur across one year. The adults take advantage of the curled leaves produced by their feeding behavior and use them as a protection to put their eggs. The immature stages, after hatching, remain inside the shelter provided by the curled leaf. They are transparent in the first two instars and then become light yellow. Only the last, adult stage, is black.
Since the Cuban laurel thrips makes ornamental plants ugly, humans are always trying to find ways to kill them, especially by using pesticides or, sometimes, natural predators of the thrips. But the little insect can also fight back. When the thrips accidentally fall on people’s bodies, they tend to bite, most likely by accident, but this can end up causing a serious and annoying itch. That’s the price for messing with them.
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Denmark HA, Fasulo TR, Funderburk JE (2005) Cuban laurel thrips, Gynaikothrips ficorum (Marchal) (Insecta: Thysanoptera: Phlaeothripidae). DPI Entomology Circular 59
Paine TD (1992) Cuban Laurel Thrips (Thysanoptera: Phlaeothripidae) Biology in Southern California: Seasonal Abundance, Temperature Dependent Development, Leaf Suitability, and Predation. Annals of the Entomological Society of America 85(2): 164–172. doi: 10.1093/aesa/85.2.164
Piu G, Ceccio S, Garau MG, Melis S, Palomba A, Pautasso M, Pittau F, Ballero M (1992) Itchy dermatitis from Gynaikothrips ficorum March in a family group. Allergy 47(4): 441–442. doi: 10.1111/j.1398-9995.1992.tb02087.x
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