Thursday, July 19, 2012

Pericartiellus durieui, an Umbilicus rupestris parasite.

Its larva secretes hormones that cause abnormal plant growths called galls.

The beetle Pericartiellus durieui (Lucas, 1846) depends on both the crassulaceae Umbilicus rupestris for playback that if this persists, it would too.

Galls caused by Pericartiellus durieui larvae in the stems of Umbilicus rupestris. (I recommend enlarge photos with a double click).

Its scientific name, as with many animal and plant species, is not without controversy among entomologists. Many of them give it other names: Nanophyes durieui and Nanophyes Lucasi, but it seems that the name internationally accepted as valid is to Pericartiellus durieui. See European Environment Agency.

Several copies of Umbilicus rupestris galls. All images were taken guts in early May in a dry stone wall of the Parc Natural del Carrascar de la Font Roja in Alcoy, Alicante. The exuberance and diversity of the flora of this park is spectacular.

The female beetle, once it has been fertilized by a male, looking Umbilicus rupestris plants healthy and lays its eggs inside the fleshy stems, just below the plant cuticle. Following commissioning in late summer, the adults die. Thus ends the life cycle and start a new one.

Previous galls with details of the inflorescence of Umbilicus rupestris who barely been able to develop, as the parasite larvae secrete hormones that inhibit flowering, to ensure their galls the contribution of substantially all of the water and nutrients up from the roots of the host.

Two plants of Umbilicus rupestris with galls.

Previous galls with details of the inflorescence inhibited by hormones of the parasite.

In this image of Umbilicus rupestris healthy with long inflorescences and stems without galls very well appreciate the differences between parasitized plants. 

Several galls halved to view its contents.

In early fall the eggs hatch inside the stems of Umbilicus rupestris and the larvae begin to secrete hormones that cause an exaggerated and abnormal growth of plant tissues that surround it, as if they were true cancerous tumors called galls. This tumor tissue serves as food for the larvae and also protects it from predation by insectivorous birds and it can withstand the cold long winter.

In the right half of this gall is the head of a larva of Pericartiellus durieui and half left transparent larva after another tumor tissues.

The larvae grow in the fall, winter and spring fed by the moist tissues of the barb, digging in her galleries as they feed. In early summer the larva undergoes a metamorphosis and becomes a nymph.

 Above larva with an arrow.

In the upper right half of this gall can see a small white larva.

Previous larva about 3 millimeters long and 1 mm thick with brown head and white body.

During the first weeks of summer, the pupa is gradually metamorphosing their internal organs and in September becomes an adult beetle, a tiny coleopter a few millimeters, which opens an outlet in the gall cuticle and emerge outside. Then the female emits sexual pheromones to attract males flying towards her, copulate and fertilize their eggs. After copulation the males die and the mated female flies in search of healthy Umbilicus rupestris to lay their eggs, after which she dies. And again begins the peculiar life cycle.

Pericartiellus durieui adult insect. This image is owned by the magnificent website: