DNA metabarcoding analysis of three material types to reveal Joro spider (Trichonephila clavata) trophic interactions and web capture

Abstract

Introduced species alter established trophic interactions and molecular analysis can resolve changes in community structure and associated foraging links. Joro spiders (Trichonephila clavata) were recently introduced to the United States and their range is rapidly expanding across the east coast. Here, we used DNA metabarcoding of fecal samples, prey remains from webs, and dissected guts to compare diet composition of female Joro spiders in the southeastern United States. We amplified DNA from three material types using arthropod-targeted COI primers and sequenced with IIlumina MiSeq. Prey remains from webs had the highest diversity, richness, as well as the highest proportion of prey reads relative to Joro spider reads. Recovery of prey reads from fecal samples and dissected gut content was low and both were overwhelmed by Joro spider DNA. Although fecal samples and gut content had high proportions of Joro spider reads, fecal samples had higher prey diversity and richness. Moreover, we detected prey DNA from fecal samples several days after capture from the field, which reveals initial gut retention time estimates for fecal samples collected from web-building spiders. Combined, our results offer a first glimpse at the complexity of trophic associations for an introduced web-building spider and identify a viable material, prey remains from webs, as a source of prey DNA for estimates of biodiversity associated with web-building spiders.

Do Invasive Jorō Spiders (Trichonephila clavata) from Asia Avoid Eating Unpalatable Monarch Butterflies (Danaus plexippus) in North America?

“…Our visual survey of natural prey items in jor ō spider webs revealed that butterflies in general make up a very small fraction of the jor ō diet, with the main prey base being composed of Hymenoptera and Hemiptera insects. Interestingly, these frequencies differ slightly from those of a recent study, which examined this spider's prey base in more detail [14]. In that case, the authors had used DNA barcoding to identify prey types of jor ō spiders and found that the frequencies of different types of prey differed depending on whether the gut contents were examined versus the contents of the fecal material.…”

“…In fact, based on the latest research that considered their physiology and climate suitability in their native range, they are expected to establish throughout much of eastern North America [12,13]. As such, there is much concern over how this new orb-weaver will impact the native fauna of this large region, including competition with native spiders for territory [13], and over their potential impact on insect populations [14]. Indeed, the large size of jor ō spider webs (see Figure 1), added to their extreme density within the introduced range, means that any flying insects that frequent the same habitats and spaces will be potential prey items for this spider.…”

How Urban-Tolerant Are They? Testing Prey–Capture Behavior of Introduced Jorō Spiders (Trichonephila clavata) Next to Busy Roads

“…This does not rule out the possibility that the prey composition or availability differed between sites (i.e., between busy roads compared to less busy roads), though we consider this unlikely. Further, a separate study of the jor ō spider diet has recently been published, where the stomach contents of spiders were examined from varying sites across Georgia and South Carolina [31]. The most common arthropod Orders found included Coleoptera, Diptera, Hemiptera, and Hymenoptera, though there was no indication that the diet composition varied from site to site.…”

Towards holistic insect monitoring: species discovery, description, identification and traits for all insects

“…The study of iDNA is particularly scalable and cost-effective when applied to insect faeces or regurgitates, as neither substrate requires DNA extraction [ 69 ]. Other cost-effective techniques are the analysis of fresh or archived plants for arthropod DNA [ 70 , 71 ] and the analysis of spider webs for prey DNA [ 72 , 73 ]. Occasionally, the interpretation of the signal can be difficult, but tools such as metabolite screens can even resolve whether the detected iDNA originated from carrion or dung [ 74 , 75 ].…”