Cyclical-parthenogenesis
Guides
Chydorus
Chydorus is a genus of small benthic-littoral cladocerans in the family Chydoridae, established by William Elford Leach in 1816. Species in this genus are characterized by rounded, often reticulated carapaces and are among the most common anomopods in freshwater systems worldwide. The genus exhibits cosmopolitan distribution with multiple centers of diversification in Europe and Asia, and includes ecologically significant species such as Chydorus sphaericus, which dominates eutrophic waters and plays important roles in food web dynamics involving cyanobacteria.
Feron atrimentum
Striped Volcano Gall Wasp
Feron atrimentum is a cynipid gall wasp that induces distinctive galls on blue oak (Quercus douglasii) leaves. The species exhibits cyclical parthenogenesis with alternating sexual and parthenogenic generations, each producing morphologically distinct gall types. The common name refers to the volcano-shaped galls with red stripes produced by the parthenogenic generation.
Feron pattersonae
Plate Gall Wasp
Feron pattersonae, the plate gall wasp, is a cynipid wasp that induces distinct galls on white oaks, particularly blue oak (Quercus douglasii). The species exhibits cyclical parthenogenesis with two alternating generations per year: an all-female parthenogenetic generation and a bisexual generation. Each generation produces morphologically different galls—flat, circular, plate-like galls in summer, and pointed capsule galls on hair-like stems later in the year. The bisexual generation's galls were originally described as a separate species, Andricus pedicellatus, by Alfred Kinsey in 1922.
Penilia avirostris
Penilia avirostris is a marine cladoceran crustacean in the family Sididae, distributed across temperate and tropical coastal waters worldwide. It is a holoplanktonic species that exhibits cyclical parthenogenesis, with populations shifting between asexual and sexual reproduction in response to environmental cues. The species has been observed to undergo diel vertical migration and shows strong sensitivity to temperature, with optimal growth around 18°C but tolerance ranging from 12°C to 30°C. Population dynamics are closely tied to seasonal temperature fluctuations, with dramatic increases reported in warming waters.
Philonix fulvicollis
Philonix fulvicollis is a gall wasp species in the family Cynipidae, first described by Fitch in 1859. It has an alternation of sexual and asexual generations, a phenomenon confirmed through molecular analysis of cytb and ITS2 sequences. The species is distributed across eastern and central North America, with records from the United States and Canada. Like other cynipid wasps, it induces gall formation on host plants, though specific host associations require further documentation.