The relationship between host plant traits and biodiversity across three sympatric seed-feeding tri-trophic systems in a tropical region of Brazil

We describe the diverse community of insect herbivores and parasitoids associated with the seeds and fruits of three sympatric Fabaceae species in Lavras, Minas Gerais, Brazil: Inga vera, Senna multijuga and Leucaena leucocephala.A total of 5353 individual insects, representing 77 different species, were identified via morphology and DNA barcoding. The non-native L. leucocephala had the least diverse natural enemy community (N = 17 species), while two native species, I. vera and S. multijuga, were more diverse (N = 40 and N = 24 species, respectively).Individuals from the insect order Hymenoptera, a group dominated by parasitoid wasps, were the most diverse recovered from our samples in all hosts. Additionally, individual herbivore and parasitoid species were more likely to be found on a single host, with only four out of the 77 species found in more than one plant species.This includes the generalist agricultural pest herbivore, Lasioderma serricorne, found in two species, and three parasitoids connecting native S. multijuga and non-native L. leucocephala communities, hinting at recent host shifts.Furthermore, different host plant traits had complex effects on the herbivore and parasitoid communities, where seed number per fruit promoted a propagating effect on the abundance and richness at both higher trophic levels, whereas seed and fruit weight did not.We highlight the importance of including parasitoids in insect community studies because they are highly diverse and provide important ecosystem services. Additional study of the biology, behaviour and distributions of parasitoids would be advantageous to inform conservation and biological control.