Host plant effects on morphometric characteristics of Liriomyza huidobrensis, L. sativae and L. trifolii (Diptera: Agromyzidae)

Abstract

Body size of herbivorous insects may be directly related to host plant characteristics (e.g. nutrition, chemical composition) and positively linked to performance of the herbivore and its parasitoids. Differences in adult body size of Liriomyza huidobrensis, L. sativae and L. trifolii reared on Pisum sativum, Phaseolus vulgaris, Vicia faba and Solanum lycopersicum were assessed to determine the effect of host plants on adult size. Furthermore, morphometric wing and hind tibia measurements were used to determine suitability as proxy measures for adult size. Based on canonical and linear discriminant analyses, two distinct Liriomyza morphospecies groups were recognized across all plant species. The first cluster represented L. huidobrensis and the second L. sativae and L. trifolii. The overall degree of correct classification of the three species across all plants tested (correct observation) with cross validation was estimated at 85%. Liriomyza huidobrensis, the largest species, showed no differences in the variables measured when reared on the four plant species. However, different plant species seem to influence wing and hind tibia measurements in L. trifolii to a greater extent than in L. huidobrensis and L. sativae. The first two canonical variates could not separate the populations of L. huidobrensis and L. sativae reared on different plant species, but showed separation of L. trifolii populations into two clusters: firstly, insects reared on V. faba and secondly, insects reared on P. vulgaris and S. lycopersicum. Hind tibia length strongly correlated with wing length. Both can be used to determine adult size of the three Liriomyza species. This study provides some new evidence for the existence of differential preferences by Liriomyza species for the four host plant species. This, therefore, warrants larger scale field studies to test for positive preference‐performance of Liriomyza species on these plant species and to determine possible consequences at the third tritrophic level.

Host Plant-Related Parasitism and Host Feeding Activities of Diglyphus isaea (Hymenoptera: Eulophidae) on Liriomyza huidobrensis, Liriomyza sativae, and Liriomyza trifolii (Diptera: Agromyzidae)

“…In addition, using the same host plant species and cultivars as in the current study, V. faba seemed a more suitable host plant for L. trifolii than P. vulgaris or S. lycopersicum based on adult size as a measure of performance (Musundire et al 2012), whereas parasitism was highest on S. lycopersicum. The disparity between host plant-related size variation in adult Liriomyza species (Musundire et al 2012) and the current results for leafminer-plant-related variation in parasitism and host feeding levels could be attributed to several factors, including volatile cues released by leafminer-damaged host plants (FinidoriLogli et al 1996, Zhao and Kang 2002, Wei et al 2006) and visual cues, such as the shape of a leaf mine (Sugimoto et al 1988). …”

“…Larval density on the four host plant species is strongly positively related to leaf area (Musundire et al 2012). However, larval densities did not vary significantly among the plant species tested when the leaf area ranged between 50 and 70 cm 2 (Musundire et al 2012).…”

“…The highest proportion of females of D. isaea across all the host plant species was observed for L. huidobrensis. Although host sizes of Liriomyza leafminer larvae were not measured in this study, studies by Spencer (1973) and Musundire et al (2012) showed that under uniform conditions, L. huidobrensis larvae are larger than those of L. sativae and L. trifolii, suggesting that this species should receive a higher allocation of female progeny compared with larvae of L. sativae and L. trifolii. In the current study, the proportion of females depended on host plant and Liriomyza species tested and varied between 25% (L. sativae on S. lycopersicum) and 72% (L. trifolii on V. faba).…”

“…However, larval densities did not vary significantly among the plant species tested when the leaf area ranged between 50 and 70 cm 2 (Musundire et al 2012). Thus, the plant species used were standardized by using the same age, size, fertilization regime, and leaf area (50-70 cm 2 ).…”

“…Plants were grown in red clay potting soil in plastic pots (11 cm in 2 diameter by 9 cm in depth) and maintained in a Liriomyza-free screenhouse at 27 ± 2°C and ≈30% RH at icipe in Nairobi, Kenya. One gram of a top-dressing of calcium ammonium nitrate (27% nitrogen) was added per pot 1 wk after germination or transplanting of plants.Larval density on the four host plant species is strongly positively related to leaf area (Musundire et al 2012). However, larval densities did not vary significantly among the plant species tested when the leaf area ranged between 50 and 70 cm 2 (Musundire et al 2012).…”