Host range and searching behaviour ofCricotopus lebetis(Diptera: Chironomidae), a tip miner ofHydrilla verticillata(Hydrocharitaceae)

Abstract

A chironomid midge, Cricotopus lebetis Sublette (Diptera: Chironomidae), was discovered feeding on Hydrilla verticillata (L.f.) Royle (Hydrocharitaceae) in Crystal River, Citrus, Co., Florida, in the 1990s. Larvae of the midge mine the apical meristems of hydrilla, causing terminal branching and stunting of the plant. We investigated the fundamental host range of the midge by conducting a series of no-choice and paired-choice tests. No-choice developmental tests with neonate larvae revealed that the fundamental host range of C. lebetis included not only on hydrilla but also several other aquatic plants in different families, suggesting that this insect is not a hydrilla specialist. In paired-choice bioassays, larval colonisation of Elodea canadensis Michx. (Hydrocharitaceae) and Najas guadalupensis (Spreng.) Magnus (Najadaceae) was greater than colonisation of H. verticillata. Behavioural bioassays in a Y-tube olfactometer and in Petri dishes suggested that neonate larvae were not able to locate host plant material, whereas older larvae were successful in finding hosts. In pairedchoice oviposition tests, adult females discriminated between potential oviposition sites, with greater numbers of eggs laid on E. canadensis and N. guadalupensis than on H. verticillata. This study is the first detailed account of host searching and oviposition behaviour of a phytophagous chironomid midge. The results will be used to assess the potential value of C. lebetis as a biological control agent of hydrilla.

Temperature-Dependent Development, Cold Tolerance, and Potential Distribution of Cricotopus lebetis (Diptera: Chironomidae), a Tip Miner of Hydrilla verticillata (Hydrocharitaceae)

“…Host plant availability is probably not highly limiting because at least one of the midge’s host plants, hydrilla, is found in water bodies throughout the southern United States ( Madeira et al. 2000 ), and C. lebetis has been shown to complete development in several other common aquatic plants ( Stratman et al. 2013 ).…”

Cricotopus lebetis Intraspecific Competition and Damage to Hydrilla

“…Since its discovery, C. lebetis has been evaluated for its potential as an augmentative biological control agent for hydrilla . Previous studies have focused on biology and impact (Cuda et al 2002(Cuda et al , 2011, host range and searching behavior (Stratman et al 2013b), distribution based on temperature (Stratman et al 2014), colony rearing techniques (Cuda et al 2002;Stratman et al 2014;Baniszewski et al 2015Baniszewski et al , 2016Mitchell et al 2018), and its compatibility with chemical control .…”

“…Cuda et al (2002) has described the feeding habits and performance of C. lebetis on hydrilla strains from Florida, USA; New Delhi, India; and Burundi. Stratman et al (2013b) described the performance of C. lebetis in monoecious and dioecious biotypes of hydrilla. Both the strain (Cuda et al 2002) and biotype of hydrilla (Stratman et al 2013b) had significant effects on the survival rate of C. lebetis.…”

“…Stratman et al (2013b) described the performance of C. lebetis in monoecious and dioecious biotypes of hydrilla. Both the strain (Cuda et al 2002) and biotype of hydrilla (Stratman et al 2013b) had significant effects on the survival rate of C. lebetis. However, it has not been determined how much damage an individual C. lebetis can cause, nor how it can perform in resource-poor environments.…”

Effect of Food Deprivation on Hydrilla Tip Mining Midge Survival and Subsequent Development

“…The origin of the hydrilla tip mining midge and its distribution in Florida are unknown (Epler et al 2000). However, C. lebetis has been detected occurring naturally in several lakes in Florida, albeit in low numbers (Stratman et al 2013b). Augmentative releases of the hydrilla tip mining midge require mass rearing, as well as handling and storage of eggs or larvae prior to release, which can have negative effects on larval viability.…”