Neoteny
Guides
Caenocholax
Caenocholax is a genus of twisted-winged insects (Strepsiptera) in the family Myrmecolacidae, comprising approximately nine described species. Members are endoparasitoids of ants, with documented associations including Solenopsis invicta and Camponotus planatus. The genus exhibits the extreme sexual dimorphism characteristic of Strepsiptera: males are free-living with reduced forewings and large fan-shaped hindwings, while females remain endoparasitic and neotenic within the host.
Elateroidea
Click, Firefly, and Soldier Beetles
Elateroidea is a large superfamily of beetles comprising approximately 25,000 species across multiple families. It includes the familiar click beetles (Elateridae), fireflies and glow-worms (Lampyridae and related families), and soldier beetles (Cantharidae). The superfamily exhibits remarkable morphological diversity, ranging from hard-bodied forms with five abdominal ventrites to soft-bodied forms with 7-8 ventrites connected by membranes. Bioluminescence has evolved independently in multiple lineages, particularly within the lampyroid clade and certain Elateridae. A distinctive clicking mechanism using a prothoracic peg and mesothoracic cavity is present in several sclerotized families, enabling the characteristic jumping behavior of click beetles.
Embiidina
webspinners, footspinners
Embiidina is a small order of cryptic, soft-bodied insects known as webspinners or footspinners, characterized by their unique ability to produce silk from specialized glands located in their swollen foretarsi. They construct extensive silk galleries or tunnels under bark, in leaf litter, or within soil crevices, which serve as protective shelters and foraging sites. The order exhibits pronounced sexual dimorphism: females are wingless and neotenic, remaining in galleries throughout their lives, while males of most species develop wings and disperse to locate mates. Webspinners are primarily tropical in distribution and display facultatively communal behavior with maternal care of eggs and young.
Eupathocera erynnidis
Eupathocera erynnidis is a species of twisted-wing parasite in the family Xenidae. It is an obligate endoparasite of insects, with females remaining permanently within host abdomens while males develop to a free-flying adult stage. The species has been documented in North America, including Florida. Like other strepsipterans, it exhibits extreme sexual dimorphism and complex life history adaptations associated with parasitism.
Halictophagus
Leafhopper Twistwing Parasites
Halictophagus is a genus of twisted-wing parasites (Strepsiptera) in the family Halictophagidae. These insects are endoparasitoids of leafhoppers and related Hemiptera, primarily in the families Cicadellidae and Cercopidae. The genus exhibits extreme sexual dimorphism: free-living males with reduced wings and branched antennae, and neotenic females that remain within the host. Multiple species have been described worldwide, with documented hosts including mango leafhoppers (Idioscopus spp., Bakera nigrobilineata) and other planthoppers.
Lycidae
net-winged beetles
Lycidae is a cosmopolitan family of beetles commonly known as net-winged beetles. Adults are typically elongated, 10–15 mm in length, with brick-red or black-and-orange coloration and long, serrated antennae. The family is notable for its distinctive reticulated wing venation, chemical defenses against predators, and participation in extensive Müllerian mimicry complexes with other beetles and even moths. Several lineages exhibit neoteny, with females retaining larval morphology into adulthood.
Nymphomyiidae
nymph flies
Nymphomyiidae are a family of minute (approximately 2 mm), delicate flies with highly reduced morphology. They are considered among the most archaic living Diptera, sometimes placed in their own suborder Archidiptera. Larvae are strictly aquatic, inhabiting cold, fast-flowing streams in northern and high-altitude regions. Adults are short-lived, non-feeding, and form aggregative swarms; their wings fracture at the base after mating. The family contains approximately one dozen extant species, currently classified in the single genus Nymphomyia.
Orchestia
Orchestia is a genus of talitrid amphipods comprising approximately 10-15 marine supralittoral species. The genus was revised in 2014, with three new species described from the North Atlantic and South America, and has been redefined to exclude terrestrial species now placed in Cryptorchestia. Species in this genus inhabit coastal environments including sandy beaches, driftwood, and estuaries, with some showing specialized ecological associations. Orchestia species serve as intermediate hosts for parasites and play roles in wrack decomposition.
Orchestia grillus
beach hopper, saltmarsh amphipod
Orchestia grillus is a saltmarsh amphipod in the family Talitridae, found in South America. It is notable for its role in studies of parasite-manipulated behavior, specifically involving infection by the trematode Levinseniella byrdi. Infected individuals display bright orange coloration and altered habitat use compared to uninfected individuals. The species is currently recognized as a synonym of Speziorchestia grillus in some taxonomic databases.
Palingeniidae
spiny-headed burrowing mayflies
Palingeniidae is a family of large mayflies commonly known as spiny-headed burrowing mayflies. Adults are characterized by having more than four longitudinal cross-veins on their wings, with males possessing short, wide pronota and well-developed legs in both sexes. Female cerci are shorter than the body. Nymphs are burrowers in muddy substrates of large rivers. The family includes notable species such as Palingenia longicauda, the largest European mayfly at up to 12 cm in length.
Phausis
shadow ghosts, blue ghost fireflies
Phausis is a genus of firefly beetles in the family Lampyridae, established by LeConte in 1851. The genus is notable for extreme sexual dimorphism: males are small, winged, and typically non-luminescent, while females are larviform, flightless, and bioluminescent. Ten species are described from North America, including the well-known blue ghost firefly (Phausis reticulata). The genus remains poorly studied due to the cryptic nature of its species, and its taxonomic boundaries with the related genus Lamprohiza are unclear.
Phausis inaccensa
Shadow Ghost
Phausis inaccensa, commonly called the shadow ghost, is a small firefly species notable for extreme sexual dimorphism. Females are larviform, wingless, and bioluminescent, while males possess wings but lack lanterns. The species inhabits forested areas of the central and eastern United States. Females exhibit extended parental care, guarding egg clutches until death.
Phausis nigra
Phausis nigra is a species of firefly in the beetle family Lampyridae, described by Hopping in 1937. It belongs to the genus Phausis, which includes other "shadow ghost" fireflies characterized by neotenic, wingless females that glow while flight-capable males lack lanterns. The species is found in North America, with records from British Columbia, Canada. Very little specific information has been published about this particular species.
Phausis reticulata
Blue Ghost
A firefly species in the family Lampyridae known for the distinctive blueish-white glow of males observed at night. Males are fully winged and capable of flight, producing a steady continuous glow rather than flashing patterns typical of many fireflies. Females are wingless, paedomorphic, and retain a larval body form into adulthood. The species exhibits strong sexual dimorphism in both morphology and bioluminescent display.
Phausis rhombica
Phausis rhombica is a firefly species in the beetle family Lampyridae, described by Fender in 1962. It belongs to the genus Phausis, which includes other "shadow ghost" fireflies characterized by neotenic, wingless, glowing females and winged, non-luminous males. The species is found in North America, with distribution records from Alberta, Canada.
Strepsiptera
Twisted-wing Insects, Twisted-wing Parasites, Stylops
Strepsiptera is an order of obligate endoparasitic insects comprising approximately 600 described species across 11 extant families. The group exhibits extreme sexual dimorphism: males are free-living, short-lived adults with reduced forewings modified into halteres and large fan-shaped hindwings, while females are neotenic, larviform, and remain permanently within their insect hosts. All strepsipterans are parasites of other insects, with documented hosts spanning seven orders including Hymenoptera, Hemiptera, Orthoptera, Blattodea, Mantodea, Zygentoma, and Diptera. The order is believed to be most closely related to Coleoptera, forming the clade Coleopterida.
Stylopidae
Stylopidae is a family of obligate parasitic insects in the order Strepsiptera, comprising approximately 15 genera and over 330 described species. All members are endoparasites of bees (Hymenoptera), with infected hosts referred to as "stylopized." Females are neotenic, remaining within the host body throughout their adult life, while males are free-living with reduced morphology. The family exhibits extreme sexual dimorphism and a unique reproductive strategy involving traumatic insemination via a paragenital organ.
Stylops
stylops
Stylops is a genus of obligately endoparasitic insects in the family Stylopidae, order Strepsiptera. Members are endoparasites of Hymenoptera, particularly bees in the family Andrenidae. The genus exhibits extreme sexual dimorphism: males are free-living with wings and functional limbs, while females are neotenic, legless, and remain permanently embedded within host abdomens with only the cephalothorax protruding. The genus has cosmopolitan distribution with numerous described species, though taxonomic status of many remains problematic due to reliance on poor female morphological characters.
Talitridae
Sandhoppers, Landhoppers
Talitridae is a family of amphipod crustaceans encompassing diverse ecological forms including beach-dwelling sandhoppers, terrestrial landhoppers, and specialized driftwood hoppers. Members occupy habitats ranging from marine intertidal zones to fully terrestrial environments in rainforest leaf litter and caves. The family exhibits remarkable physiological adaptations for desiccation resistance and aerial respiration, with some Southern Hemisphere species being entirely terrestrial. Ecological diversity within Talitridae includes wrack generalists, psammophilic burrowers, palustral salt marsh dwellers, xylophagous driftwood specialists, and freshwater forms.
Xenidae
twisted-wing parasites
Xenidae is a family of endoparasitic twisted-wing insects (Strepsiptera) comprising approximately 13 genera and over 120 described species. Members are obligate endoparasites primarily of social wasps and hornets (Hymenoptera: Vespidae), though some genera parasitize other wasp families including Sphecidae and Bembicidae. The family exhibits extreme sexual dimorphism: males are free-living with reduced forewings and functional hindwings, while females are neotenic, legless, and permanently embedded within their hosts with only a cephalothorax protruding. Molecular studies indicate substantial cryptic species diversity, with actual species numbers likely at least double current descriptions.
Xenos
twisted-wing parasites
Xenos is a genus of twisted-wing parasites in the order Strepsiptera. These insects are obligate endoparasites of other insects, with larvae entering hosts through joints or sutures. Adult males are free-flying and short-lived, while neotenic females remain permanently within host abdomens. The genus includes species such as Xenos peckii, which parasitizes wasps including Polistes fuscatus.
Zootermopsis angusticollis
Pacific Dampwood Termite
Zootermopsis angusticollis is a dampwood termite species native to the Pacific coast of North America. It is among the largest termites in North America and is notable for its strict dependence on moist, decaying wood. The species is eusocial, living in colonies with distinct castes including workers, soldiers, nymphs, and reproductives. It has been extensively studied as a model organism for hindgut symbiont ecology and represents one of the best-studied lower termites in terms of gut microbial communities.