Strepsiptera Biology and Host-Parasite Dynamics

Strepsiptera are a small order of obligate endoparasitic insects, notable for extreme sexual dimorphism and a life cycle intimately tied to their hosts, predominantly Hymenoptera and Hemiptera. First-instar larvae actively seek out hosts, penetrate the integument and develop internally, emerging as neotenic females or free-living males. Females remain largely unrecognisable from within the host, producing pheromones to attract winged males and releasing infective larvae into the environment. Hosts undergo physiological and behavioural manipulation, including castration, altered foraging and de facto dispersal roles that facilitate parasite transmission. Morphological simplification in adult females contrasts with elaborate male flight structures, reflecting an evolutionary trade-off between reproductive strategy and host exploitation. Recent advances in imaging, genomics and behavioural observation have illuminated Strepsiptera’s phylogenetic relationships, host specificity and mechanisms of host manipulation, with implications for understanding parasitic co-evolution and potential biocontrol applications.

Research from Nature Portfolio

Studies have revealed that strepsipteran mating involves traumatic insemination even in derived endoparasitic lineages. Micro-computed tomography has shown that the male penis perforates a cephalothoracic invagination in Stylops females, and that polyandry and prolonged copulation help reduce sperm competition. Moreover, a novel paragenital organ appears to mitigate injury costs to females. Another key development demonstrated that infection by Xenos vesparum can extend the lifespan of Polistes dominula workers. Workers harbouring a female parasite survive to overwinter akin to future queens, likely enhancing parasite fitness by promoting spring transmission. Differences in fat-body reserves rather than ovary development or body size underpin this longevity manipulation, illustrating sophisticated host-parasite physiological interplay.

Strepsiptera Biology and Host-Parasite Dynamics publication trend

The graph below shows the total number of articles in strepsiptera biology and host-parasite dynamics across all publications each year (not limited to Nature Index journals).

Technical terms

Endoparasitism: A parasitic mode in which the parasite lives within the host’s body.

Traumatic insemination: A reproductive strategy where the male pierces the female’s integument to transfer sperm.

Polyandry: A mating system in which a female mates with multiple males.

Paragenital organ: A specialised structure that reduces injury during traumatic insemination.

Mitogenome: The complete mitochondrial genome sequence of an organism.

Host specificity: The degree to which a parasite is restricted to particular host species or genera.

References

1. Traumatic insemination and female counter-adaptation in Strepsiptera (Insecta). Scientific Reports (2016).
2. The female cephalothorax of Stylops ovinae Noskiewicz & Poluszyński, 1928 (Strepsiptera: Stylopida). Arthropod Systematics & Phylogeny (2016).
3. A Strepsipteran parasite extends the lifespan of workers in a social wasp. Scientific Reports (2021).
4. Preference of Polistes dominula wasps for trumpet creepers when infected by Xenos vesparum: A novel example of co-evolved traits between host and parasite. PLOS ONE (2018).
5. Xenos yangi sp. nov.: A new twisted-wing parasite species (Strepsiptera, Xenidae) from Gaoligong Mountains, Southwest China. ZooKeys (2022).
6. A generic classification of Xenidae (Strepsiptera) based on the morphology of the female cephalothorax and male cephalotheca with a preliminary checklist of species. ZooKeys (2022).
7. A needle in a haystack: Mesozoic origin of parasitism in Strepsiptera revealed by first definite Cretaceous primary larva (Insecta). PeerJ (2018).