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Transgenerational effects on overall fitness : influence of larval feeding experience on the oviposition behaviour of seed beetle Acanthoscelides obtectus (Say)

Stojković B., Seslija Jovanović D., Tucić N.

Polish Journal of Ecology

2012

Vol. 60, nr 2

387-393

Oviposition behaviour is recognized as an ecologically significant trait in insects. Since herbivorous insect females have a potential to lay eggs on unsuitable host species, it is hypothesized that this behaviour may be the first step in host-range expansion. The most intriguing phenomenon, found in some insect species, is the ability of females to lay eggs on unsuitable places if hosts are unavailable; this behaviour is termed "egg-dumping". Egg-dumping can be adaptive plastic response in environments where hosts, either preferred or less suitable, may eventually become available. Transgenerational effects of this behaviour presume changes in larval feeding experience on different host species. Also, diverse larval experience may induce alterations in oviposition behaviour. To test whether egg laying behaviour of adult females can be modified by larval experience, we performed the experiment on two laboratory populations of Acanthoscelides obtectus (Say). First population (P) is housed in the laboratory on the common bean for 200 generations, whereas the second population (C) is derived from the first but has been raised for 197 generations on chickpea, a novel and less suitable host for larval development. In order to analyze differences between short-term and long-term effects of larval experience on eggdumping, both populations have been exposed to each host seed for one generation. The results of the study show that females from P population lay eggs more frequently in the absence of seeds when developed on chickpeas, compared with P females reared on beans. By contrast to P females, in C population, larval experience has no significant effects either on the number of dumped eggs or on the frequency of dumper females. These results demonstrate a significant inter-population diversification of phenotypic plasticity in egg-dumping behaviour depending on larval host experience. In other words, modification of oviposition behaviour, as a consequence of a long-term larval nutritional stress, can evoke previously unrecognized transgenerational effects.

Effect of genetic relatedness on the allometric relationship between biomass investment and sexual reproduction in clonal plant

Stojković B., Barisic Klisaric N., Avramov S., Tarasjev A.

Polish Journal of Ecology

2009

Vol. 57, nr 2

371-375

In order to analyze changes in biomass allocation patterns across genetically structured populations where plants are competing for access to light, we performed glasshouse experiment with controlled genetic identity of competitors. Clonal replicates of 17 Lamium maculatum (L.) genotypes were grown in three treatments: control (low competition for light availability), intraclonal and interclonal competition. It was shown that competition between genetically unrelated individuals (interclonal treatment) was the most stressful environment for Spotted Dead Nettle. Results of allometry analyses, based on standardized major axis (SMA) mathematical procedure, have shown the smallest differences in relative investment to sexual reproduction between larger and smaller individuals when competing with unrelated plants. Our results indicate that allometric relationships between vegetative and reproductive traits could be strongly affected by genetic relatedness of competing plants.