Habitat odors

In addition to habitat odors, odors produced from the animal itself may be used as homing signals. The salamanders Plethodon cinereus and Plethodon jordani can distinguish between their own markings and those of conspecifics (Tristram, 1977), between the substrate markings of familiar... 

The human taste threshold for PCP in drinking water is about 30 pg/L (USEPA 1980), a level far below the upper safe limit of 1.01 mg/L and near the no-observable-effect level of 21 pg/L (Table 23.7). Odor detection is not as sensitive as taste the odor threshold for PCP ranges from about 857 pg/L at 30°C, to 1600 pg/L at 20 to 22°C, to 12,000 pg/L at 60°C (USEPA 1980). It is not clear whether the determined organoleptic threshold values made the water undesirable or unfit for consumption (USEPA 1980). If fish and wildlife species of concern have PCP organoleptic thresholds that are similar to those of humans, or lower, will they too avoid contaminated habitats or diets ... 

Aquatic animals use their chemical senses in all aspects of their lives, from reproductive behavior to feeding, habitat selection, and predator avoidance. The hydrodynamic properties determine the possibilities and limits of chemical communication in water. As a medium, water is as dynamic as air, so that convection and advection are far more important for odor transport than is diffusion. Distribution by currents is even more important in water because compounds of similar molecular weight diffuse four orders of magnitude more slowly than in air (Gleeson, 1978). Diffusion of odorants may be important only in the submillimeter range, while turbulence is typical for water masses above the centimeter range. 

In isolated male mice, own odor regulates the amount of urine deposited in marking. If it is present, they mark less, while clean surfaces and also other males urine trigger more frequent marking (Daumae and Kimura, 1986). In our laboratory experiments, students are impressed by how a mouse stops at a clean tile in the middle of a soiled open field. A scent-the-habitat function for odors from both sexes has been assumed for the gland secretions in the brushtail possum, Trichosurus vulpecula, since no sex differences in chemical composition were found (Woolhouse etal., 1994). 

Many fruits attract birds by colors, odors, and taste. After consuming the fruit, the birds will disperse the seeds to new habitat. Preference orders exist, and some fruits are rarely eaten by birds (see p. 306). For instance, the flavor of buckthorn, Rhamnus cathartica, ranked lowest of 11 fruit extracts tested in blackbirds, Turdus merula, and a song thrush, Turdusphilomelus (Sorensen, 1983). Least preferred fruits contain toxins that deter birds, perhaps to avoid seeds being dispersed to unfavorable habitat. For instance, it is disadvantageous for forest... 

Given how sensitive many birds are to odors, breeders of endangered bird species may be able to use food and environmental odors to imprint young birds on relevant cues of their future habitat (Nevitt, in Malakoff, 1999). 

For odors to work, certain environmental conditions have to be met. Townsend s voles, Microtus townsendii, avoid a repellent odor if no cover is available. With cover present, they feed whether or not the area is scented. Therefore, for effective area repellents, the pest rodent should be able to retreat to unscented areas in preferred habitat such as sufficient cover (Merkens etal, 1991 Table 13.2). 

Insects are the most diverse group animals on earth, with approximately five million species described to date (Novotny et al. 2002). Amidst this great diversity are adaptations common to all insects that maximize inclusive fitness in their respective habitats. One such fundamental adaptation is the ability to respond to cues in the environment, in particular the ability to detect external biological compounds via a chemical sensor. The sophisticated olfactory system of insects is able to sense volatile odorants derived from prey, host plants, and conspecific individuals. These compounds are detected by olfactory receptor neurons (ORNs) housed in the antennae, and these ORNs relay information about food sources, oviposition sites, and mates that leads to behavior based on neural responses mediated by the ORNs. The binding... 

When the lateral filament of an antennule flicks, it samples a small slice of the water in a crustacean s environment. What are the patterns of odor concentrations in the water samples captured by flicking antennules as the animals move through habitats exposed to ambient water motion ... 

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