| parent-offspring conflict and motivational control of brooding in an amphipod (crustacea). | models of parent-offspring conflict concerning levels of caregiving centre on conflict resolution by offspring control, compromise or offspring 'honest signalling' that parents use to maximize their own fitness. recent empirical studies on motivational control of parental feeding of offspring are interpreted as supporting the latter model. here, we examine parental care in an amphipod, crangonyx pseudogracilis, which directs care to embryos in a brood pouch. embryo removal and transplantation el ... | 2006 | 17148273 |
| lethal and sublethal toxicity of ammonia to native, invasive, and parasitised freshwater amphipods. | in lethal and sublethal ammonia toxicity tests, we examined differences in tolerance of three species of freshwater amphipods, one native and two invasive in ireland. the native gammarus duebeni celticus was slightly less tolerant to ammonia than the invasive g. pulex (96 h lc50= 1.155 and 1.544 mg l(-1), respectively), while another invader, crangonyx pseudogracilis, had the lowest tolerance (lc50= 0.36 mg l(-1)). parasitism of g. pulex by the acanthocephalan echinorhynchus truttae greatly redu ... | 2004 | 15223278 |
| parasite-mediated predation between native and invasive amphipods. | parasites can structure biological communities directly through population regulation and indirectly by processes such as apparent competition. however, the role of parasites in the process of biological invasion is less well understood and mechanisms of parasite mediation of predation among hosts are unclear. mutual predation between native and invading species is an important factor in determining the outcome of invasions in freshwater amphipod communities. here, we show that parasites mediate ... | 2003 | 12816645 |
| bioaccumulation kinetics of the organochlorine pesticide mirex in amphipods. | the survival of hyallela azteca was found to be reduced relative to that of crangonyx pseudogracilis during exposure to mirex in water for a 13-day period. this phenomenon appeared to be correlated to greater bioaccumulation of mirex by h. azteca than by c. pseudogracilis. h. azteca was found to exhibit two-compartment kinetics, while c. pseudogracilis was described by single-compartment kinetics. the bioaccumulation differences between the two species were the result of both uptake and clearanc ... | 1983 | 6872914 |
| active brood care in an amphipod: influences of embryonic development, temperature and oxygen. | female amphipods (crustacea) carry their fertilized eggs in an external brood pouch until the fully formed juveniles emerge (passive brood care). they may also direct specific maternal activities towards the brood (active brood care). we show that crangonyx pseudogracilis, which typically populates fresh-waters subject to wide fluctuations in temperature and dissolved oxygen, engages in a highly responsive form of active brood care. this involves a flexing motion by the female that expands the b ... | 1998 | 9784215 |
| differential physico-chemical tolerances of amphipod species revealed by field transplantations. | physico-chemical regimes of river systems are major determinants of the distributions and relative abundances of macroinvertebrate taxa. other factors, however, such as biotic interactions, may co-vary with changes in physico-chemistry and concomitant changes in community composition. thus, direct cause and effect relationships may not always be established from field surveys. equally, however, laboratory studies may suffer from lack of realism in extrapolation to the field. here, we use balance ... | 2000 | 28308402 |
| the enemy of my enemy is my friend: intraguild predation between invaders and natives facilitates coexistence with shared invasive prey. | understanding and predicting the outcomes of biological invasions is challenging where multiple invader and native species interact. we hypothesize that antagonistic interactions between invaders and natives could divert their impact on subsequent invasive species, thus facilitating coexistence. from field data, we found that, when existing together in freshwater sites, the native amphipod gammarus duebeni celticus and a previous invader g. pulex appear to facilitate the establishment of a secon ... | 2014 | 25122739 |
| invasion success of fibrillanosema crangonycis, n.sp., n.g.: a novel vertically transmitted microsporidian parasite from the invasive amphipod host crangonyx pseudogracilis. | parasitism is known to be an important factor in determining the success of biological invasions. here we examine crangonyx pseudogracilis, a north american amphipod invasive in the united kingdom and describe a novel microsporidium, fibrillanosema crangonycis n.sp., n.g. the primary site of infection is the female gonad and the parasite is transovarially transmitted to the eggs. pcr screening reveals a female bias in the distribution of parasites (96.6% of females, n=29; 22.2% of males, n=27), ... | 2004 | 15037109 |
| suitability of crangonyx pseudogracilis (crustacea: amphipoda) as an early warning indicator in the multispecies freshwater biomonitor. | biological monitors are increasingly important in 'biological early warning systems' (bews) for monitoring water quality. this study examines the freshwater amphipod crangonyx pseudogracilis as a potential new indicator species when used in the multispecies freshwater biomonitor (mfb). the mfb is an online continuous biomonitor which uses impedance conversion to record behavioural responses of vertebrates and invertebrates. | 2006 | 16910122 |
| sodium uptake and loss in crangonyx pseudogracilis (amphipoda) and some other crustaceans. | | 1975 | 240560 |