In biogeography, vicariance and long-distance dispersal are often characterised as competing scenarios. However, they are related concepts, both relying on collective geological, ecological, and phylogenetic evidence. This is illustrated by freshwater fishes, which may immigrate to islands either when freshwater connections are temporarily present and later severed (vicariance), or by unusual means when ocean gaps are crossed (long-distance dispersal). Marine barriers have a strong filtering effect on freshwater fishes, limiting immigrants to those most capable of oceanic dispersal. The roles of vicariance and dispersal are debated for freshwater fishes of the Greater Antilles. We review three active hypotheses [Cretaceous vicariance, Greater Antilles-Aves Ridge (GAARlandia), long-distance dispersal] and propose long-distance dispersal to be an appropriate model due to limited support for freshwater fish use of landspans. Greater Antillean freshwater fishes have six potential source bioregions (defined from faunal similarity): Northern Gulf of México, Western Gulf of México, Maya Terrane, Chortís Block, Eastern Panamá, and Northern South America. Faunas of the Greater Antilles are composed of taxa immigrating from many of these bioregions, but there is strong compositional disharmony between island and mainland fish faunas (>90% of Antillean species are cyprinodontiforms, compared to <10% in Northern Gulf of México and Northern South America, and ≤50% elsewhere), consistent with a hypothesis of long-distance dispersal. Ancestral-area reconstruction analysis indicates there were 16 or 17 immigration events over the last 51 million years, 14 or 15 of these by cyprinodontiforms. Published divergence estimates and evidence available for each immigration event suggests they occurred at different times and by different pathways, possibly with rafts of vegetation discharged from rivers or washed to sea during storms. If so, ocean currents likely provide critical pathways for immigration when flowing from one landmass to another. On the other hand, currents create dispersal barriers when flowing perpendicularly between landmasses. In addition to high salinity tolerance, cyprinodontiforms collectively display a variety of adaptations that could enhance their ability to live with rafts (small body size, viviparity, low metabolism, amphibiousness, diapause, self-fertilisation). These adaptations likely also helped immigrants establish island populations after arrival and to persist long term thereafter. Cichlids may have used a pseudo bridge (Nicaragua Rise) to reach the Greater Antilles. Gars (Lepisosteidae) may have crossed the Straits of Florida to Cuba, a relatively short crossing that is not a barrier to gene flow for several cyprinodontiform immigrants. Indeed, widespread distributions of Quaternary migrants (Cyprinodon, Gambusia, Kryptolebias), within the Greater Antilles and among neighbouring bioregions, imply that long-distance dispersal is not necessarily inhibitory for well-adapted species, even though it appears to be virtually impossible for all other freshwater fishes.

The genus Gambusia represents approximately 45 species of polyandrous livebearing fishes with reversed sexual size dimorphism (i.e. males smaller than females) and with copulation predominantly via male coercion. Male body size has been suggested as an important sexually selected trait, but despite abundant research, evidence for sexual selection on male body size in this genus is mixed. Studies have found that large males have an advantage in both male-male competition and female choice, but that small males perform sneaky copulations better and at higher frequency and thus may sire more offspring in this coercive mating system. Here, we synthesized this inconsistent body of evidence using pre-registered methods and hypotheses. We performed a systematic review and meta-analysis of summary and primary (raw) data combining both published (n = 19 studies, k = 106 effect sizes) and unpublished effect sizes (n = 17, k = 242) to test whether there is overall selection on male body size across studies in Gambusia. We also tested several specific hypotheses to understand the sources of heterogeneity across effects. Meta-analysis revealed an overall positive correlation between male size and reproductive performance (r = 0.23, 95% confidence interval: 0.10-0.35, n = 36, k = 348, 4,514 males, three Gambusia species). Despite high heterogeneity, the large-male advantage appeared robust across all measures studied (i.e. female choice, mating success, paternity, sperm quantity and quality), and was considerably larger for female choice (r = 0.43, 95% confidence interval: 0.28-0.59, n = 14, k = 43). Meta-regressions found several important factors explaining heterogeneity across effects, including type of sperm characteristic, male-to-female ratio, female reproductive status and environmental conditions. We found evidence of publication bias; however, its influence on our estimates was attenuated by including a substantial amount of unpublished effects, highlighting the importance of open primary data for more accurate meta-analytic estimates. In addition to positive selection on male size, our study suggests that we need to rethink the role and form of sexual selection in Gambusia and, more broadly, to consider the ecological factors that affect reproductive behaviour in livebearing fishes.

The effectiveness of spinosad for larval mosquito control is summarized based on available published literature and some heretofore unpublished studies. Spinosad is highly active against larvae of all mosquito species tested thus far. It is effective at similar dosages for all larval mosquito instars, with peak cumulative mortality occurring at 72 h posttreatment. More studies are needed to fully define spinosad\'s ovicidal properties and its impact on the pupal stage. High levels of organic matter and full sunlight are both factors that can negatively impact spinosad efficacy and longevity and should be considered when making use rate and retreatment decisions. Studies clearly show that spinosad technical active ingredient and current crop formulations are suboptimal for larval mosquito control and underrepresent spinosad\'s true activity. A series of spinosad formulations specialized for larval mosquito control will be sold commercially. Prior to its launch and widespread use, there is a need for additional baseline studies to clarify the natural geographic variation in susceptibility of field mosquito populations. Spinosad represents a new and effective natural product for the integrated management of larval mosquitoes. It possesses a unique mode of action not shared by any other insecticide and is shown to be minimally disruptive to most nontarget species tested thus far at its proposed field use rates.

A review is being presented concerning behavioural, biochemical, histochemical and electronmicroscopical data on the influence of altered gravitational forces on the swimming performance and on the neuronal differentiation of the brain of cichlid fish larvae and adult swordtail fish that had been exposed to hyper-gravity (3g in laboratory centrifuges), hypo-gravity (>10(-2) g in a fast-rotating clinostat) and to near weightlessness (10(-4) g aboard the Spacelab D-2 mission). After long-term alterations of gravity (and parallel light deprivation), initial disturbances in the swimming behaviour followed by a stepwise regain of normal swimming modes are induced. Parallel, neuroplastic reactivities on different levels of investigation were found, such as adaptive alterations of activities of various enzymes in whole brain as well as in specific neuronal integration centers and an intraneuronal reactivity on ultrastructural level in individual brain parts and in the sensory epithelia of the inner ear. Taken together, these data reveal distinct adaptive neuroplastic reactions of fish to altered gravity conditions.

Three peptide toxins exhibiting strong paralytic activity to molluscs, but with no paralytic effects on arthropods or vertebrates, were purified from the venom of the molluscivorous snail Conus textile neovicarius from the Red Sea. The amino acid sequences of these mollusc specific toxins are: TxIA, WCKQSGEMCNLLDQNCCDGYCIVLVCT (identical to the so-called \'King Kong peptide\'); TxIB, WCKQSGEMCNVLDQNCCDGYCIVFVCT; TxIIA, WGGYSTYC gamma VDS gamma CCSDNCVRSYCT (gamma = gamma-carboxyglutamate). There is a similarity of the Cys framework of these toxins to that of the omega-conotoxins; however, their net negative charges, high content of hydrophobic residues, and uneven number of Cys residues in TxIIA are highly unusual for conotoxins. When assayed on isolated cultured Aplysia neurons, all three toxins induced spontaneous repetitive firing. The TxI toxins also induced a marked prolongation of the action potential duration. Voltage clamp experiments revealed that the TxI toxins alter the kinetics of the sodium current either by slowing down the rate of sodium current inactivation, or by recruiting silent sodium channels with slower activation and inactivation kinetics. The toxins shift the voltage-dependent steady-state Na+ current inactivation curve to more positive values by 6 mV. These changes are not associated with alteration in the rate of INa+ activation, in the peak INa+, or the sodium current reversal potential. TxI represents a new class of conotoxins with an unusual phylogenic specificity and may therefore be useful as a probe for the study of voltage gated sodium channels. (This review summarizes previously published papers).