The relationship among host plant species, egg clutch size, and level of parasitism for the sharpshooter Tapajosa rubromarginata

Abstract

The sharpshooter Tapajosa rubromarginata (Signoret) (Hemiptera: Cicadellidae, Proconiini), a vector of the bacterium Xylella fastidiosa Wells et al. (Xanthomonadaceae) that causes citrus variegated chlorosis, has more than 30 reported host plant species. The fitness of a phytophagous insect is determined by the host plant suitability, plant resistance, and the natural enemies. The aim of this study was to: (1) identify plant species utilized as oviposition substrate by T. rubromarginata in the field; (2) establish the relationship between plants and clutch size; (3) establish the relationship among host plants, clutch size, and level of parasitism; and (4) establish variations in parasitoid composition and abundance in the various host plants. Egg masses of the sharpshooter were surveyed on plants reported as hosts, or those that were abundant in the study site. The number of eggs of the sharpshooter and emerged parasitoids were recorded for all the collected masses. We found egg masses of T. rubromarginata on 12 out of 21 plant species sampled. The size of the egg masses was greatly influenced by the type of leaf venation and to a lesser extent by the plant species. Parasitism rates were influenced by both leaf venation and host plant. Trichogrammatidae species were mostly associated with egg masses in plants with parallel-veined leaves, whereas Mymaridae attacked masses laid in reticular-veined leaves. The choice between a good host plant, but heavily attacked by parasitoids, and the host plants that are less suitable for nymphs but less frequently attacked by natural enemies, was a trade-off for T. rubromarginata females to increase their fitness. We conclude that the host plant utilization by T. rubromarginata females in the field could be influenced by leaf structure and the strategy to avoid parasitism by selecting plants that were less attractive for parasitoids.

Behavioral Response of The Egg Parasitoid Cosmocomoidea Annulicornis (Hymenoptera: Mymaridae) and Characterization of The Chemical Cues That Guide Females Toward Host Eggs Located In Taxonomically Distant Plants Species

“…Tapajosa rubromarginata (Signoret) (Hemiptera: Cicadellidae: Proconiini) is a polyphagous sharpshooter with a Neotropical distribution (Dellapé and Paradell 2013) that has been reported feeding and ovipositing on over 35 plant species in 17 families, some of commercial importance, such as Saccharum o cinarum L., Avena sativa L., Allium sativum L., Vitis vinífera L., Citrus sinensis L., C. limon (L.), C. unshiu and Zea mays L., but also on numerous weeds like Sorghum halepense L. (Paradell et al 2012;Dellapé 2013;Virla et al 2019Virla et al , 2020. This sharpshooter transmits the bacteria Xylella fastidiosa Wells et al (Dellapé et al 2016), causal agent of the Citrus variegated chlorosis, that affects several commercial species of Citrus, and other diseases in plants such as grape vines, almonds, olives, etc.…”

“…Common volatiles emitted in response to herbivory would be important for orientation toward the host, but oviposition could be mediated by direct contact cues. It is possible that female nal acceptance of hosts is based on other traits besides olfactory cues(Colazza et al 2009), such as leaf morphological structures(Virla et al 2020), contact cues(Iacovone et al 2016) and host quality(Hofstetter and Raffa 1998, Zhou et al 2014).…”