Search results for "Variation"
showing 4 items of 2124 documents
Plasticity in Photoperiodism : Drosophila montana Females Have a Life-Long Ability to Switch From Reproduction to Diapause
2022
Photoperiodic reproductive diapause is an essential part of female life cycle in several insect species living on high latitudes, where overwintering in reproductive stage involves high risks for survival and progeny production. The sensitive period (SP), during which photoperiodic cues can trigger the switch from direct development to diapause, can last from a few hours or days after emergence to the entire life span of females. Moreover, in some species, sexually mature females can enter post-reproductive diapause as a response to decreasing day length and/or temperature. We studied the duration of SP for diapause induction and the females’ ability to enter post-reproductive diapause at s…
Multimodal Aposematic Signals and Their Emerging Role in Mate Attraction
2018
Chemically defended animals often display conspicuous color patterns that predators learn to associate with their unprofitability and subsequently avoid. Such animals (i.e., aposematic), deter predators by stimulating their visual and chemical sensory channels. Hence, aposematism is considered to be “multimodal.” The evolution of warning signals (and to a lesser degree their accompanying chemical defenses) is fundamentally linked to natural selection by predators. Lately, however, increasing evidence also points to a role of sexual selection shaping warning signal evolution. One of the species in which this has been shown is the wood tiger moth, Arctia plantaginis, which we here put forward…
Kaksivuotiaiden lasten fonologisen kehityksen variaatio : puheen ymmärrettävyyden sekä sananmuotojen tavoittelun ja tuottamisen tarkastelu
2007
Torvelainen selvitti kaksivuotiaiden lasten fonologisen eli äänteellisen kehityksen variaatiota. Edistyneimmät kaksivuotiaat puhuivat lähes aikuismallisesti, kun taas heikoimpien lasten puhe poikkesi vielä suuresti aikuismallista. – Äänteellistä kehitystä tutkittaessa pitää ottaa huomioon lapsen sanavarasto. Jos kaksivuotiaalla on pieni sanasto, on normaalia, että hänen puheensa poikkeaa vielä paljon aikuismallisesta puheesta. Suuri sanavarasto puolestaan liittyi hyvin aikuismaiseen kieleen, Päivi Torvelainen kertoo.Edistyneimpien kaksivuotiaiden tuottamat sanat olivat niin aikuissanojen kaltaisia, että heidän puheestaan lasta tuntematon aikuinen ymmärsi lähes kaiken (96 %), kun taas heikoi…
Rearing background and exposure environment together explain higher survival of aquaculture fish during a bacterial outbreak
2019
1.Parasitic diseases represent one of the greatest challenges for aquaculture worldwide and there is an increasing emphasis on ecological solutions to prevent infections. One proposed solution is enriched rearing, where traditional stimulus‐poor rearing tanks are equipped with different types of structures to increase habitat complexity. Such spatial enrichment is known to increase survival of fish during parasite epidemics, but the underlying mechanisms are still unclear. 2.We studied whether enriched rearing affected infection of an important fish pathogen Flavobacterium columnare in young Atlantic salmon (Salmo salar) and sea‐migrating brown trout (Salmo trutta). First, we used natural b…