Larvae development

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After hatching, the larva remains within its own cell for a few days. In this days it gradually completes the process of pigmentation, from white to gray until the complete melanization. The first portion of the body that changes of color is the abdomen followed by legs, head, antennae and prothorax (Sturani, 1947). The larvae develop through three larval stages (defined by the letters L1, L2, L3); they are of type campodeiform with the head with a square shape, devoid of the region of the neck, and the body rather narrow and elongated with urogonfi seats at the rear end of the abdomen. After the first two or three days of inactive life inside the cell, the larva in the first stage (L1) starts to move actively in search of prey, mainly consisting of small gastropods and arthropods alive. Unlike adults, mainly polyphagous, the larvae are very demanding with regard to the feeding. After the first larval stage, which typically lasts 12 days, takes place the first moult. This process occurs in ground sheltered areas, or below stones of an medium size. The second-stage larva (L2) behaves essentially as in the previous case, but due to its increased size it can feed on a wider range of prey. After about 11 days takes place the second and final moult. At this point the larva of the third stage (L3) will continue to grow to reach the size of 34 mm after about 13 days. Similarly to adults all larval stages are active during the night, especially after sunset and into the morning. During the day they take refuge under the litter or below the stones in order to avoid excessive exposure to sunlight which would entail the death by dehydration. At the end of the third larval stage (L3) the larva begins to dig into the ground a cell for pupation in a depth of about 10-30 cm. After a few days the preparation of the cell is completed; compared to those of the larva, it has a larger size (55 X 40 X 28 mm). At this point, if the environmental conditions (T, humidity, etc..) are favorable the animal locates supine in the cell and begins the process of pupation. It is common, due to a particularly adverse weather conditions, or in response to a late ovideposiziopne that the larvae reach maturity very late (late August, early September). In these circumstances the L3 stage does not come to pupation, but enter into quiescence (diapause larvae) until the beginning of next spring. It 'obvious that in this case the biological cycle will not be annual, it will be biennial, due to the adults of these larvae of "long cycle" will appear only the following summer. This phenomenon has a clear adaptive significance, to prevent pupation in times inadequate for the third-stage larvae that have had a late development.