Morphometry, allometry, and fluctuating asymmetry of egg parasitoid Trichogramma pretiosum under insecticide influence

Abstract

The morphometric analysis of parasitoids may contribute to biological control programs by providing information on development of insects and relationships among sizes of morphological characters. Furthermore, it can infer about the impact of insecticides on morphological characters and fitness. We evaluate the morphometry, allometry, and fluctuating asymmetry of the egg parasitoid Trichogramma pretiosum Riley (Hymenoptera: Trichogrammatidae) with and without influence of the growth-regulating insecticides teflubenzuron and lufenuron. Trichogramma pretiosum had significantly larger wings and tibiae in treatments with insecticides. We found no effects of insecticides on asymmetry in T. pretiosum and conclude that this insect is very close to isometry. This study emphasizes the importance of evaluating the size of parasitoids destined to biological control programs.

Selectivity of deltamethrin doses on Palmistichus elaeisis (Hymenoptera: Eulophidae) parasitizing Tenebrio molitor (Coleoptera: Tenebrionidae)

“…Reduction of the P. elaeisis head width and the metatibia length after exposure to the lowest deltamethrin doses may be due to the fact that parasitoids within certain limits, adjust their size to that of the host with food resource availability and number of parasitoids inside it 42 with lower foraging and parasitism on hosts with smaller body biomass 43 . The reduction of the P. elaeisis morphometric parameters can compromise its competitiveness and physical fitness, because mating capacity is correlated with body size 44 . Therefore, this biological parameter may affect its potential as a biological control agent.…”

Can multitrophic interactions shape morphometry, allometry, and fluctuating asymmetry of seed-feeding insects?

“…For the hymenopteran species A . vulgaris , we measured total body size length (thorax + abdomen) [ 43 , 49 , 50 ], +R vein until the end of 3RSb vein, wing width measured from the junction between anterior wing length measured from the beginning of C+Sc, the parastigma and stigma to the end of vein 1A ( Fig 2C ) (adapted from [ 44 ]); and posterior tibia length was measured from the junction of the femur and the tibia to the junction of the tibia and tarsus [ 23 , 35 ]. Wings and tibia from the wasp A .…”

“…To test these hypotheses, we selected the morphological traits that best explain the body size variation in some species of bruchine beetles [ 20 , 23 ], namely pronotum length, left and right elytra and biomass; and for the wasp: right and left wing, right and left tibia length, and total body length of A . vulgaris [ 43 , 44 ]. We evaluated the size, the allometric relationships and the fluctuating asymmetry of these morphological traits, according to different categories of seed infestation, parasitism rate and seed biomass to investigate the possible influence of these variables on the morphological structures of these species.…”

Untitled

“…The structure measurements in the two coleopteran species were pronotum width, and both left and right elytra length and width [20,23] (Fig 2A and 2B). For the hymenopteran species A. vulgaris, we measured total body size length (thorax + abdomen) [43,49,50], +R vein until the end of 3RSb vein, wing width measured from the junction between anterior wing length measured from the beginning of C+Sc, the parastigma and stigma to the end of vein 1A ( Fig 2C) (adapted from [44]); and posterior tibia length was measured from the junction of the femur and the tibia to the junction of the tibia and tarsus [23,35]. Wings and tibia from the https://doi.org/10.1371/journal.pone.0241913.g001…”