The parasitoid species complex associated with sexual and parthenogenetic Naryciinae (Lepidoptera: Psychidae): Integrating ecological and molecular analyses

Abstract

Abstract. This study describes the parasitoid species complex associated with seven closely related species of sexual (Siederia rupicollella, S. listerella, Dahlica lazuri, D. charlottae and D. lichenella) and parthenogenetic (Dahlica fennicella and D. triquetrella) Naryciinae (Lepidoptera: Psychidae) in Central Finland. A thorough ecological analysis of all the species of parasitoids recorded was combined with analyses of molecular data. Mitochondrial and nuclear DNA data were obtained from all the species in order to (1) detect cryptic species associated with host specialization, (2) assign undescribed males to females, and (3) verify the morphological identification of closely related species. A DNA barcoding technique was employed to identify host species from parasitized larval remains. By sampling more than 10,000 host larvae, of which 25.7% were parasitized, nine parasitoid species were identified morphologically, including both koinobionts (Ichneumonidae: Diadegma incompletum, Macrus parvulus, Trachyarus borealis, T. solyanikovi, T. fuscipes, T. brevipennis and Braconidae: Meteorus affinis) and idiobionts (Ichneumonidae: Orthizema flavicorne, Gelis fuscicornis).Ecological characteristics such as time and mode of host attack, time of emergence and level of specialization differed widely. The results show that differences in parasitoid biology need to be taken into account when studying differences in percentage parasitism of sexual and parthenogenetic Naryciinae. The molecular data revealed that one parasitoid species M. parvulus may consist of two cryptic forms associated with the sexual and parthenogenetic hosts, respectively. The data further establishes that T. brevipennis and some T. fuscipes are in fact morphotypes of one species. The large variation in mitochondrial DNA within species and its inconsistency with nuclear DNA demonstrate that current species and genus delimitation is inadequate in the Trachyarus species group. Our study shows that it is essential to use DNA barcoding methods when investigating host-parasitoid complexes.

Evaluation of criteria for species delimitation of bagworm moths (Lepidoptera: Psychidae)

“…In drosophilids none of the distance threshold criteria were suitable for delimiting species (Yassin et al, 2010). The same situation is reported for two species of parasitoids (Trachyarus solyanikovi and T. fuscipes) (Elzinga et al, 2011a). Strutzenberger et al (2011) even suggest a species specific threshold value of 2% for Eois moths.…”

“…Despite all the possible disadvantages of a short fragment, the analysis of COII resulted in the same species specific clusters as that of COI. Moreover, the amplification of COII in degraded tissues was particularly useful for identifying parasitized bagworm moths (Elzinga et al, 2011a.…”

Low parasitism rates in parthenogenetic bagworm moths do not support the parasitoid hypothesis for sex

“…In this system, sexual species coexist in the same habitat with a closely related obligate parthenogen ( Dahlica fennicella ; Elzinga et al ., ). Their larvae are attacked and killed by eight species of hymenopteran parasitoids, exerting a very strong selective pressure (Kumpulainen, ; Elzinga et al ., ). Kumpulainen et al .…”

“…In February 2008, before the bagworm moth larvae became active, 70 forested sites around Jyväskylä, central Finland were selected (see map in Elzinga et al ., ) including several sites that were originally examined by Kumpulainen et al . ().…”

Large variation in mitochondrial DNA of sexual and parthenogenetic Dahlica triquetrella (Lepidoptera: Psychidae) shows multiple origins of parthenogenesis

“…The variation in mtDNA within D. triquetrella is often larger than that observed between several other Naryciinae species, and exceeds many proposed values to delimit species [52]. The large variation in mtDNA may be correlated with observed variation in morphology [53], and also could explain why there are several questionable species and subspecies described that are very locally distributed [16].…”