01670nas a2200157 4500008004100000245007100041210006900112260000900181300001400190490000700204520120600211100001501417700002101432700001801453856004101471 1994 eng d00aParasite manipulation of host behaviour: should hosts always lose?0 aParasite manipulation of host behaviour should hosts always lose c1994 a479 - 4840 v703 a

Parasites of all kinds alter the behaviour of their hosts. In many systems, these behavioural modifications appear adaptive for the parasite, by facilitating the completion of its life cycle. However, not all parasitized hosts are under the influence of parasites. This may be due to the timing of the onset of behavioural manipulation by the parasites: changes in behaviour may coincide with completed parasite development and only appear late in the infection. In addition, certain hosts may oppose the parasite's attempts at manipulating their behaviour. Hosts with high expected future reproductive success, i.e. young hosts or hosts that have not yet reproduced, are more likely to benefit by opposing the influence of parasites, as their expected gains would outweigh the costs of opposition. Such conditional opposition would be a better alternative to resistance to infection itself if resistance is costly, and would explain the considerable variability often observed in the behavioural responses of parasitized hosts. Future tests of these ideas should give insights into the coevolution of hosts and parasites and the parasites' struggle for the control of host behaviour.

1 aPoulin, R.1 aBrodeur, Jacques1 aMoore, Janice uhttps://www.jstor.org/stable/354578802082nas a2200133 4500008004100000245006900041210006700110260000900177300001400186490000700200520165000207100001801857856007301875 2000 eng d00aSpite, xenophobia, and collaboration between hosts and parasites0 aSpite xenophobia and collaboration between hosts and parasites c2000 a396 - 4000 v913 a

Results of current computer simulations suggest that a pathogen-mediated version of Hamilton’s spite hypothesis may play an unexpected role in the evolution of host-parasite interactions. Theory predicts that hosts’ ability to influence parasite transmission to conspecifics is a neutral character provided that transmission routes are random. There are two possible deviations from this. Firstly, vertical transmission is biased in favour of kin, and this selects hosts to decrease pathogen transfer. Secondly, horizontal transmission is biased against kin and this selects hosts to increase pathogen transfer to conspecifics. Unfortunately, we typically do not know transmission statistics in relation to genetic kinship within a host population, thus cannot easily predict whether there is a selective pressure upon hosts either to transmit pathogens or not to transmit. Here I aim to show that even simple descriptive information on host and parasite life-histories may be used to make rough estimations about transmission routes and selection pressures. Interspecific predictions suggest that pelagic hosts, passively aerial hosts, and the intermediate hosts of pathogens transmitted along the predator-prey transmission routes are not selected to influence pathogen transmission. Intraspecific predictions suggest that parasitism and disease should facilitate emigration, and immigrants surrounded by non-related conspecifics should adaptively enhance pathogen transmission to conspecifics. This behaviour may select social animals, like humans, for an adaptive xenophobia in the context of an intraspecific arms-race.

1 aRózsa, Lajos uhttp://www.phthiraptera.info/sites/phthiraptera.info/files/43348.pdf01906nas a2200157 4500008004100000245009300041210006900134260000900203300001400212490000700226520136900233100002101602700002101623700002201644856008201666 2002 eng d00aLow humidity reduces ectoparasite pressure: Implications for host life history evolution0 aLow humidity reduces ectoparasite pressure Implications for host c2002 a223 - 2280 v973 a

A parasite’s potential effect, or ‘‘pressure’’, can influence the life history strategy of its host. In environments with high parasite pressure, hosts invest more in anti-para- site defense, which may limit their investment in other life history components, such as survival. This tradeoff is difficult to study in natural populations because pressure is hard to quantify. Pressure is not necessarily correlated with the abundance of the parasite. A host population can be under high pressure, yet have few parasites, because members of the population have invested heavily in defense. Therefore, the extent to which parasite pressure varies among host populations, and the cause of such variation, remain largely undocumented. In this paper we show that birds in arid regions have fewer ectoparasitic lice than birds in humid regions. We show experimentally that low humidity reduces the number of lice on birds, even when host defense is held constant. Comparisons of ambient humidity to humidity beneath the plumage demonstrate that plumage does not provide a buffer for lice against low humidity. Our results confirm that an abiotic factor can cause substantial variation in parasite pressure among host populations. We suggest that humidity may influence host life history evolution through its impact on ectoparasites.

1 aMoyer, Brett, R.1 aDrown, Devin, M.1 aClayton, Dale, H. uhttps://phthiraptera.myspecies.info/sites/phthiraptera.info/files/41854_0.pdf02932nas a2200325 4500008004100000245008700041210006900128260000900197300001400206490000700220520207200227653001402299653001302313653000902326653001602335653001002351653001102361653001402372653001302386653001602399653001102415653001302426653001002439653001302449653000902462653001202471100002202483700002002505856008102525 2001 eng d00aInfluence of host ecology and morphology on the diversity of Neotropical bird lice0 aInfluence of host ecology and morphology on the diversity of Neo c2001 a455 - 4670 v943 a

Host-parasite systems can be powerful arenas in which to explore factors influencing community structure. We used a comparative approach to examine the influence of host ecology and morphology on the diversity of chewing lice (Insecta: Phthiraptera) among 52 species of Peruvian birds. For each host species we calculated two components of parasite diversity: 1) cumulative species richness, and 2) mean abundance. We tested for correlations between these parasite indices and 13 host ecological and morphological variables. Host ecological variables included geographic range size, local population density, and microhabitat use. Host morphological variables included body mass, plumage depth, and standard dimensions of bill, foot and toenail morphology, all of which could influence the efficiency of anti-parasite grooming. Data were analysed using statistical and comparative methods that control for sampling effort and host phylogeny. None of the independent host variables correlated with louse species richness when treated as a dependent variable. When richness was treated as an independent variable, however, it was positively correlated with mean louse abundance. Host body mass was also positively correlated with mean louse abundance. When louse richness and host body mass were held constant, mean louse abundance correlated negatively with the degree to which the upper mandible of the host's bill overhangs the lower mandible. This correlation suggests that birds with longer overhangs are better at controlling lice during preening. We propose a specific functional hypothesis in which preening damages lice by exerting a shearing force between the overhang and the tip of the lower mandible. This study is the first to suggest a parasite-control function of such a detailed component of bill morphology across species. Avian biologists have traditionally focused almost exclusively on bills as tools for feeding. We suggest that the adaptive radiation of bill morphology should be reinterpreted with both preening and feeding in mind.

10aabundance10aBehavior10abody10acommunities10adoves10afishes10ageography10agrooming10aindependent10amarine10aparasite10arange10arichness10arock10aspecies1 aClayton, Dale, H.1 aWalther, B., A. uhttps://phthiraptera.myspecies.info/sites/phthiraptera.info/files/3266_0.pdf02544nas a2200313 4500008004100000245012400041210006900165260000900234300001400243490000700257520170300264653001201967653001001979653001101989653000902000653001502009653001802024653001502042653002102057653000902078653001302087653000902100653001202109653001302121100001402134700001402148700002602162856004202188 1998 eng d00aEffects of a dipteran ectoparasite on immune response and growth trade-offs in barn swallow, Hirundo rustica, nestlings0 aEffects of a dipteran ectoparasite on immune response and growth c1998 a217 - 2280 v813 a

Parasites can have a profound effect on biology and evolution of the hosts, which are expected to have evolved physiological and developmental mechanisms that allow them to minimise the costs imposed by parasites. In this study we analyse the effects of a dipteran ectoparasite on barn swallow (Hirundo rustica) nestling biology including rate of somatic growth, plasma protein concentration, blood cell sedimentation rate, hematocrit, concentration of leukocytes in peripheral blood, and T-lymphocyte cell-mediated immunocompetence. In a natural population, intensity of parasite infestation was positively correlated with growth of feathers. Nestlings in heavily infested nests may decide to allocate more resources to feather growth thus fledging early. To test this hypothesis, the detrimental effects of parasites on nestlings, and the existence of trade-offs between competing growth processes, we inoculated some nests with additional flies. Nestlings exposed to increased infestation had larger rate of feather growth but were in poorer condition than unmanipulated controls. Parasite inoculation resulted in larger concentrations of eosinophils and lymphocytes. Among siblings of broods inoculated with parasites, those that had the largest rate of feather growth had the lowest rate of increase in tarsus length and body mass. We conclude that louse flies depress barn swallow nestling condition and influence their immune profile. However, they also enhance growth of a morphological character that may allow nestlings to reduce the impact of parasites. Nestlings apparently experience a trade-off between the competing demands for growing feathers and other somatic characters.

10achicken10acliff10aclutch10acost10ahematology10ahematophagous10ahypothesis10aimmunocompetence10amite10aparasite10asize10asuccess10aswallows1 aSaino, N.1 aCalza, S.1 aMøller, Anders, Pape uhttps://www.jstor.org/stable/3547043 02241nas a2200313 4500008004100000245009400041210006900135260000900204300001400213490000700227520137600234653001101610653001901621653001601640653001201656653001401668653001601682653001301698653001301711653001401724653001201738653001401750653001101764653001801775100002001793700002201813700002001835856007201855 1999 eng d00aShowiness of neotropical birds in relation to ectoparasite abundance and foraging stratum0 aShowiness of neotropical birds in relation to ectoparasite abund c1999 a157 - 1650 v873 a

The evolution of bird coloration has inspired many hypotheses. We report the results of comparative tests involving the interacting effects of microhabitat use, sexual selection and parasite transmission on colour evolution. We used a data set of chewing lice (Insecta: Phthiraptera) sampled from 122 Neotropical bird species to test Hamilton and Zuk's prediction that species subjected to high parasite ''pressure'' evolve showy trails that enhance the ability of females to choose parasite free mates. We found no significant relationship between mean parasite abundance and showiness among the 122 species. However, for the 66 non-passerine species in the data set, we found a significant negative relationship between parasite abundance and showiness, contrary to the Hamilton and Zuk prediction. These results are discussed in light of recent work on parasite-mediated sexual selection. We also tested for a relationship between showiness and the microhabitat use of different species of rainforest birds. Like other authors, we found a significant positive relationship between showiness and foraging stratum among the 113 species analysed. While drab species occur in all forest strata, showy species occur mostly in the midstorey and canopy. We discuss variables which may influence the evolution of such a pattern among forest birds.

10abright10aclassification10acomparative10aecology10aEvolution10aindependent10amediated10aparasite10aPhylogeny10aplumage10aselection10asexual10awood warblers1 aWalther, B., A.1 aClayton, Dale, H.1 aGregory, R., D. uhttp://www.phthiraptera.info/sites/phthiraptera.info/files/1228.pdf