Review of the aquatic Hemiptera from Cephalonia, with a checklist for the Ionian Islands, Greece (Heteroptera: Gerromorpha, Nepomorpha, Leptopodomorpha)

Eleven species of aquatic true bugs (Hemiptera: Heteroptera) are newly recorded for Cephalonia Island (Greece)—Gerromorpha: Hydrometra stagnorum (Linnaeus, 1758), Microvelia pygmaea (Dufour, 1833), Velia mariae Tamanini, 1971, Gerris argentatus Schummel, 1832, G. costae (Herrich-Schäffer, 1850), G. lacustris (Linnaeus, 1758); Nepomorpha: Corixa affinis Leach, 1817, Anisops crinitus Brooks, 1951, A. sardeus Herrich-Schäffer, 1849, Notonecta maculata Fabricius, 1794, Plea minutissima Leach, 1817—where only a few species have been recorded. The most notable records are: Anisops crinitus, which in Europe was known only from the island of Corfu (Greece) and Spain (until recently under the name A. marazanofi Poisson, 1966), and Velia mariae, whose distribution is still poorly known. Velia rivulorum (Fabricius, 1775), V. currens (Fabricius, 1794), and Anisops canariensis Nouahlier, 1893 (currently A. debilis canariensis), from old literature records, are excluded from the fauna of the Ionian Islands. Similarly, N. glauca glauca Linnaeus, 1758 is excluded from the fauna of Cephalonia and Corfu. The first record of Hydrometra gracilenta Horváth, 1899 from Corfu and for the Ionian Islands is provided. Microvelia pygmaea and Gerris maculatus Tamanini, 1946 are newly recorded for Lefkada Island. An annotated list of the Gerromorpha, Nepomorpha, and Leptopodomorpha of the Ionian Islands also is given.

Size-selective dispersal of Daphnia resting eggs by backswimmers ( Notonecta maculata )

Freshwater zooplankton is increasingly used to study effects of dispersal on community and metacommunity structure. Yet, it remains unclear how zooplankton disperses. Clearly, birds and wind play a significant role as zooplankton dispersal agents, but they may not always be the main vectors. This experimental study shows that a cosmopolitan aquatic insect, Notonecta , can be an important vector of cladoceran resting eggs (ephippia). Dispersing Notonecta frequently transported ephippia during flight, with a bias towards smaller ephippia in two species. A similar trend was present at the species level: Daphnia species with smaller ephippia were more often dispersed, suggesting that Notonecta could generate specific colonist communities. In addition, buoyancy appeared a critical trait, as non-floating ephippia of Daphnia magna were never dispersed. Our data suggest that Notonecta could be important dispersers of Daphnia , and that knowledge of dispersal dynamics of Notonecta may be used to predict Daphnia dispersal, colonization and resilience to disturbance.