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ŠUMARSKI LIST 1-2/2013 str. 56     <-- 56 -->        PDF

The development of caterpillars – Razvoj gusjenica
The development of caterpillars of L. dispar came through six instars according to the sex of a future imago, differences being noted in the duration of particular instars depending on the quality of food.
The shortest total development was determined in the 1st–3rd instars of caterpillars in treatments T1 (32 days) and T2 (34 days). Slower development occurred in treatments T3 (40 days) and T0 (47 days). Statistically significant differences were proved among all treatments with the exception of T1 and T2, T0 and T3 at the 1st instar, T2 and T3 at the 2nd instar, T1 and T2 at the 3rd instar (Fig. 4).
In treatments T1–T3, a trend was kept of the prolongation of the development of caterpillars in the 1st instar (11–12–15), the 2nd instar (12–13–14) and the 3rd instar (9–9–11).
Because caterpillars were reared individually from the 4th instar, a difference was determined in the duration of particular instars between caterpillars of future males and females regardless of the quality of  ingested food. Duration of the 4th and 5th instars (males 16, 21 days, females 14, 13 days) and the period of pupae (males 21 days, females 17 days) were statistically significantly longer at males than at females (p < 0.001 at the level of significance α=0.05). However, the total duration of the development of males is shorter as compared to females with respect to the absence of the 6th instar, which took at females on average 22 days.
The length of the development of the 4th and 5th instars of caterpillars of future males showed the same dependence on the food quality as the 1st–3rd instars. However, differences at the 4th instar were not significant (T0/18, T1/15, T2/16, T3/17 days). At the 5th instar, a difference was statistically significant between control treatment (T0/26 days) and all other treatments (T1 and T2/20 days, T3/21 days) (p = 0.001–0.022) (Fig. 5).