Search

Parasitic plants and herbivores show similarities in their interactions with host plants. Herbivore‐induced resistance/susceptibility in plants can scale up to the arthropod community. Similar evidence regarding parasitic plants is scarce. We evaluated the indirect effects initiated by the mistletoe Tristerix aphyllus on the arthropod community of the cactus Echinopsis chiloensis in the Chilean coastal desert. Field observations suggested that a stem‐borer beetle bores more brood chambers in mistletoe‐parasitised cacti than in non‐parasitised cacti, and that arthropods colonise these chambers.We compared tissue toughness, chamber density and morphology in mistletoe‐parasitised and non‐parasitised cacti. We also compared richness, total abundance, abundance per taxa, diversity and composition of the colonising arthropod community.Parasitised cacti showed a 14% reduction in tissue toughness. Chamber density in parasitised cacti was four times greater and chambers were larger: 35% more volume, an entrance‐opening area 30% greater, and twice the area of the maximum‐width section. Arthropod species richness and diversity were higher in chambers of parasitised cacti. Arthropod community composition was different in chambers of parasitised and non‐parasitised cacti. Thus, spiders and moths were more abundant in parasitised cacti, and pseudoscorpions, scolopendras, ants and flies were exclusively present there, while non‐parasitised cacti had no exclusive taxa.Mistletoe infection results in a richer, more diverse and distinct arthropod community on its cactus host, which occurs through induced susceptibility to stem‐borers whose brood chambers are colonised by arthropods. Tristerix aphyllus could be a key‐stone species in these arid ecosystems, where arthropod diversity is relatively low. [ABSTRACT FROM AUTHOR]

Delia platura Meigen is an important pest in crops around the world. Its host range includes almost 50 species, and it can develop in soil organic matter. In Ecuador, D. platura is a serious problem for the crop, Lupinus mutabilis Sweet (Chocho), and it also attacks broccoli (Brassica oleracea L.). After broccoli is harvested, crop residue is mixed with soil or collected and stored close to Chocho fields. The objectives of this study were to determine the adaptive responses of larvae reared on different hosts and whether D. platura females are preferentially attracted to germinating L. mutabilis seeds or broccoli residue. Accordingly, larval performance and attraction of female D. platura reared on broccoli residue and L. mutabilis seeds were evaluated. The number of larvae, pupae, and adults were higher when reared on broccoli. Conversely, pupal weight was higher and time from larva to pupa, pupa to adult, and total life cycle were longer in flies reared on L. mutabilis. Although D. platura developed more quickly on broccoli, L. mutabilis was also a good host since pupae were heavier compared with flies reared on broccoli. Delia platura females reared on broccoli preferred broccoli residue to L. mutabilis in an olfactometer. Volatiles from broccoli residue in soil may attract D. platura females and stimulate oviposition on L. mutabilis seeds. Environmentally benign production of L. mutabilis crops with minimal insecticide applications may require the elimination of fresh broccoli residue as fertilizer in soils where L. mutabilis is cultivated. [ABSTRACT FROM AUTHOR]