Aposematic

Terrick T.D., Mumme R.L. and Burghardt G.M. (1995). Aposematic coloration enchances chemosensory recognition of noxious prey in the garter snake Thamnophis radix. Anim Behav 49, 857-866. 

Utetheisa, like many other Lepidoptera of the family Arctiidae, is aposematic. White, with pink hindwings and black and yellow markings (Figure 1 A), it is highly conspicuous on the wing. It flies as readily in daytime as at night. We suspected the moth to be unpalatable, and we were able to prove this in experiments with orb-weaving spiders. 

Adult Utetheisa tend to be rejected also by birds (blue jays, Cyanocitta cristata scrub jays, Apkelocoma coemlescens T.E., unpublished observations), as might be expected, given their aposematism, but there is no definitive evidence that the unacceptability is due specifically to the PAs. 

A prominent characteristic of most true bugs is their use of defensive chemicals produced in specialized scent glands, usually found in the abdomen in im-matures, and in the metathorax in adults. However, this pattern is not absolute species that feed on poisonous plants from which they sequester toxic chemical defenses tend to have reduced or modified glands [8,26-28]. Many of these species are also aposematic, vividly advertising their toxicity to would-be predators. The defensive chemistry of bugs has been the subject of a number of reviews [4,6,8,9,12,29,30] and will only be summarized here, with a focus on compounds with interesting or unusual chemistry. 

Aposematic species from two different families produce pungent pyrazines, presumably as an additional warning to potential predators of their toxicity. These include Oncopeltus fasciatus (Lygaeidae, seed bug family) that secretes 2-isobutyl-3-methoxypyrazine [28], and the stink bug Murgantia histrionica (Pentatomidae), that oozes froth containing 2-isobutyl- and 2-sec-butyl-3-methoxypyrazine when molested [39]. 

Defensive Compounds. The aposematically coloured Chauliognathusfallax which feed on Senecio brasiliensis (Asteraceae) sequester the four pyrrolizidine alkaloids senecionine (100 main compound), integerrimine (101 main compound), retrorsine 102, and usaramine 103 [203] (Scheme 11). Other Chauliognathus-species may contain either precoccinelline 104 and related alkaloids (C. pul-chelus) or Z-dihydromatricaria acid 105 (C. pennsylvanicus). 

When disturbed or molested, these insects release small droplets of hemo-lymph from the tibio-femoral joints of their legs, and it is now well established that the deterrency exhibited by many species of coccinellids towards potential predators results from the presence of repellent and bitter alkaloids in that fluid [ 12,13]. In ladybirds, this unpalatability is associated with a bright aposematic coloration and a characteristic smell due to 3-alkyl-2-methoxypyrazines [14, 15]. The beetles use these molecules not only to reinforce the visual alerting signal on an olfactory level, but also as aggregation pheromones [16]. 

Many aposematic lepidopteran insects are associated with poisonous plants and sequester the toxins from their host instead of, or in some cases in addition to, biosynthesizing their own defensive compounds. 

Aposematically colored, the yellow-bellied sea snake, Pehmis platurus (Hydrophiidae), of the eastern Pacific has venom and is distasteful. It has no known aquatic predators, although remains were found in murray eels and sharks. Predatory fish such as snappers refuse the snake. They reject its meat even when hidden in palatable squid. Predatory fish of the Atlantic ocean, however, ate the sea snake in experiments, and died after 1 of 12 meals (Rubinoff and Kropach, 1970). 

Olfactory aposematism (Eisner and Grant, 1981) means associating an odor by conditioning (experience) with an odorless toxin such as nicotine, morphine, or strychnine. This is probably widespread among mammals. First the animal tastes the plant and finds it either impalatable or suffers ill effects. After that. 

Two speculative possibilities relate to olfactory aposematism. The first is whether there are non-toxic plants that smell or taste like toxic ones. In other words, do plants practice Batesian mimicry. Such mimicry is unlikely, as mammalian herbivores constantly sample plants and thereby test for favorable and adverse effects of eating a particular species. Furthermore, given the keen sense of smell of mammals, two plant species would have to exactly smell alike for mimicry to work. Second, do two distasteful or toxic plant species smell or taste alike so that herbivores can more easily classify dangerous plants and avoid them (Mullerian mimicry) (Eisner and Grant, 1981 Lindroth, 1988 Augner and Bernays, 1998). 

Visual and chemical cues interact in foraging by natricine snakes. Even visual cues alone can elicit prey attack, especially in aquatic foraging (Drummond, 1985). Aposematic color patterns of prey enhance the learning of prey that induces illness. Garter snakes, Thamnophis radix hay deni, were exposed to fish and earthworms presented on black-and-yellow forceps, and then inj ected with lithium chloride (LiCl). Control prey was offered on green forceps. Later, the snakes avoided food from either forceps, but the aversion to prey paired with black-andyellow was stronger (Terrick etal, 1995). 

Olfactory aposematism association of food toxicity with naturally occurring odor, journal of Chemical Ecology 11,1289-1295. 

Eisner, T. and Grant, R. P. (1981). Toxicity, odor aversion and olfactory aposematism. Science 213,213-476. 

Nicolaus, L. K. (1987). Conditioned aversions in a guild of egg predators implications for aposematism and prey defense mimiciy. American Midland Naturalist 117 405-419. 

Becerro MA, Starmer JA, PaulVJ, Chemical defenses of cryptic and aposematic gastropterid molluscs feeding on their host sponge dysidea gtznuXosz., Journal of Chemical Ecology 52 (7) l491—1500, 2006. 

The aposematic beetle, Metriorrhynchus rhipidius, contains three pyrazines as warning odor components and two amides as bitter principles (Tables III, V, and VIII) (97). Of the three components with the beetlelike odor, the most characteristic is 2-methoxy-3-isopropylpyrazine (24b). The other two components are 2-methoxy-3-methylpyrazine (24a) and 2-methoxy-3-sec-butylpyrazine (24d). It would seem likely that these compounds will occur in the defensive systems of the aposematic beetles. The two amide components, detectable in the hemo-lymph exuded by adult beetles, are 3-phenylpropanamide (130) and l-methyl-2-quinolone (57), the latter being the major component. It seems likely that these bitter principles contribute to distastefulness to potential predators. 

The structure of l-methyl-2-quinolone (57), from the aposematic beetle in the genus Metriorrhynchus (Table V), was expected from the mass spectral data and was confirmed by comparison with an authentic sample (97). 

Phenylpropanamide (130), from the aposematic beetle (genus Metrior-rhynchus) (Table VIII), has been purified by gas chromatography from the methanol extract. Its structure is presumed from mass spectral data and was confirmed by comparison with a synthetic sample (97). The co-occurrence of amide 130 and l-methyl-2-quinolone (57) in this beetle suggests a common pathway of biosynthesis and that they may be derived from the amino acid phenylalanine. 

The members of the family Arctiidae, which numbers over 11 000 species, are often brilliantly colored (Watson and Goodger, 1986 Holloway, 1988 Weller etal, 2000a). In addition to standard aposematic red, yellow, or black patterns, adults and larvae may have iridescent blue and green, or even pearly white, coloration. White can be considered aposematic when individuals rest conspicuously on green vegetation. Numerous species are involved in mimicry rings with other distasteful species. Many adults are superb Mullerian mimics of lycid beetles, bees, wasps,... 

Aposematic caterpillars life styles of the warningly colored and unpalatable. In Caterpillars Ecological and Evolutionary Constraints on Foraging, eds. N. E. 

Dunning, D. C. and Kruger, M. (1995). Aposematic sounds in African moths. Biotropica 27 227-231. 

Roque-Albelo, L., Schroeder, F. C., Conner, W. E. et al. (2002). Chemical defense and aposematism the case for Utetheisa galapagensis. Chemoecology 12 153—... 

British aposematic Lepidoptera. In The Moths and Butterflies of Great Britain and Ireland, Part 2, eds. J. Heath and A. M. Emmet, pp. 9-62. Colchester Harley Books. 

Wink, M. L. D. and Schneider, D. (1988). Carrier-mediated uptake of pyrrolizidine alkaloids in larvae of the aposematic and alkaloid-exploiting moth Creatonotus. Naturwissenschaften 75 524-525. 

Becerro MA, Starmer JA, Paul VJ (2006) Chemical Defenses of Cryptic and Aposematic Gastropterid Molluscs Feeding on Their Host Sponge Dysidea granulosa. J Chem Ecol 32 1491... 

Young, C. M. and Bingham, B. L., Chemical defense and aposematic coloration in larvae of the ascidian Ecteinascidia turbinata, Mar. Biol., 96, 539, 1987. 

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