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The osphradium in the genus Conus is a prominent bi-lamellate structure lying in the mantle roof near to the base of the siphon. Fine structural examination shows that the component cells are organised into a peripheral and a central region. The peripheral region consists of pigmented epidermal cells forming prominent ridges between which are grooves, at the sides of which lie the sensory cells, protected in clefts. The central region is clearly differentiated from the peripheral by a prominent basement membrane. This region contains smooth muscle, paired nerve trunks and a discrete area of cells containing numerous, dense, cored vesicles. 相似文献
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Paul J. Weldon 《Chemoecology》2004,14(1):1-4
Summary. Many animals acquire substances on their integument from heterospecifics
through anointing. In active or self-anointing, animals rub against scent
sources or they apply them by appendage or mouth. In passive anointing, animals
adsorb emitted chemicals. Most investigators suggest that chemicals appropriated
via anointing deter predators, ectoparasites, and/or microbial pathogens. Similarly,
nesting birds and brood parasites of social insects acquire chemicals from and reside
unmolested near or within insect colonies. The acquisition through anointing of
chemicals that deter predators, ectoparasites, microbial pathogens, and other
offenders, i.e. defensive anointing, constitutes an extended phenotype: the
genetic machinery by which defensive compounds are synthesized does not reside with
the anointing organisms, but the sensory mechanisms and/or behavioral tendencies by
which chemicals are appropriated from heterospecifics do. The ecological
relationships between anointing organisms and chemical donors, and between
chemical donors and those responding to chemicals appropriated via anointing, may
be unorthodox. Interactions between anointing organisms and chemical donors typically
entail abrasive contact with or other damage to the latter. These encounters sometimes
are evidenced by telltale marks on chemical donors or by chemicals deposited on the
integument of anointing organisms. The organisms furnishing chemicals and those
affected by them may not interact, and they may even occupy different habitats, because
mobile anointing organisms are the medium by which chemicals are disseminated. Thus,
in allelochemical studies where anointing is involved, species can be tested, with
ecological legitimacy, using chemicals from organisms they might fail to interact with
in nature. Practical implications of anointing stem from its potential importance in
conservation and captive management, where consideration is given to the protection
that animals derive by accessing topically acquired chemicals from heterospecifics. 相似文献
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Weldon RH Barr DB Trujillo C Bradman A Holland N Eskenazi B 《Journal of environmental monitoring : JEM》2011,13(11):3136-3144
Currently, there is no nationally representative human milk biomonitoring program in the United States (U.S.) and no studies have reported non-persistent pesticides in the milk of U.S. women. In this pilot study we developed a multiresidue laboratory method to measure non-persistent and persistent pesticides and polychlorinated biphenyl (PCB) congeners in human milk samples from women residing in the agricultural region of Salinas, CA (n = 13) and the urban San Francisco Bay Area, CA (n = 21). Samples were collected from 2002-2007. Median concentrations in pg g(-1) milk among urban and agricultural women, respectively were reported for: chlorpyrifos (24.5 and 28.0), cis-permethrin (81.9 and 103), trans-permethrin (93.1 and 176), hexachlorobenzene (191 and 223), β-hexachlorocyclohexane (220 and 443), o,p'-DDT (36.6 and 62.4), p,p'-DDT,(107 and 102), o,p'-DDE (5.65 and 5.17), p,p'-DDE (3170 and 3490), dacthal (2.79 and 3.43), PCB 118 (92.8 and 17.0), PCB 138 (183 and 38.2), PCB 153 (242 and 43.6) and PCB 180 (239 and 683). Among urban women, median concentrations were 4.02 and 4.32 pg g(-1) milk for chlorpyrifos-methyl and propoxur, respectively. These results suggest that neonates and young children may be exposed to persistent and non-persistent pesticides and PCBs via breast milk. 相似文献
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Neotropical monkeys of the genus Cebus anoint themselves by rubbing arthropods and plants against their pelage. A recent study has shown that free-ranging wedge-capped capuchin monkeys ( C. olivaceus) in Venezuela self-anoint with a benzoquinone-secreting millipede, an activity by which they are hypothesized to appropriate chemical deterrents of mosquitoes. To evaluate the plausibility of this hypothesis, female yellow fever mosquitoes ( Aedes aegypti) were presented with two millipede secretory compounds, 2-methyl-1,4-benzoquinone and 2-methoxy-3-methyl-1,4-benzoquinone, on nylon-reinforced silicone membranes placed over wells filled with human blood, a highly preferred food. Mosquitoes exhibited fewer landings, fed less frequently, and flew more frequently (a possible indication of repellency) in the presence of membranes treated with benzoquinones than with controls. These compounds also elicit self-anointing in captive male and female tufted ( C. apella) and white-faced ( C. capucinus) capuchin monkeys. 相似文献
6.
The local resource enhancement (LRE) model predicts that in cooperatively breeding species, sex ratios will be biased in favor
of the more helpful sex. In this study, we assess the assumptions underlying the LRE model in a population of cooperatively
breeding wild dogs (Lycaon pictus) in Northern Botswana monitored over a 15-year period. In this population, litter size and pup survival to 1 year are strongly
affected by pack size and the breeding female’s age, but adult males have a stronger and more linear effect on females’ reproductive
performance than do adult females. This asymmetry in the benefits derived from male and female helpers is reflected in male-biased
sex ratios in litters at the time pups emerge from the den. Sex ratio biases are most pronounced in the litters of the youngest
mothers who live in significantly smaller packs than older females. The presence of potential rivals for the dominant female’s
position depresses pup production at the time of emergence, suggesting that competition among females for breeding positions
may also contribute to the selective forces affecting birth sex ratios. 相似文献
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Paul J. Weldon 《Chemoecology》2013,23(4):201-202
Discussions of aposematism traditionally have focused on the visual displays of prey that denote unpalatability or toxicity to predators. However, the construct of aposematism accommodates a spectrum of unprofitable traits signaled through various sensory modalities, including contact and distance chemoreception. Aposematism, involving learned aversions by signal receivers or selection for their unlearned avoidances, arises in predator–prey or other interspecific interactions where a mutually beneficial avoidance of signal emitters by signal receivers exists. Aposematism evolves by selection against signal receivers, e.g., predators, imposed by signal emitters, e.g., unprofitable prey, and vice versa, where both nondiscriminating signal receivers and unrecognized signal emitters are imperiled. Chemical aposematism entails concurrent reciprocal selection where signal emitters select for chemosensory avoidance responses in signal receivers, and where signal receivers select for the emission of identifiable (distinctive) chemicals in signal emitters. 相似文献
8.
Field experiments were conducted from dusk to dawn off St. John (18° 18′ 59.32″ N, 64° 43′ 24.5″ W) and Guana Island (18°
28″ 28.31″ N, 64° 34′ 30.83″ W), Virgin Islands from June through August 2008-2010 to assess the sensory cues used by the
nocturnal/crepuscular fish-parasitic gnathiid isopod, Gnathia marleyi, to locate fish hosts. Experimental traps providing both visual and olfactory cues from live French grunts (Haemulon flavioliniatum) attracted significantly more gnathiids than traps providing only visual cues or control traps (empty or with a rock), which
were not significantly different from each other. In another experiment, traps providing both cues and only olfactory cues
attracted significantly more gnathiids than empty control traps, but were not significantly different from each other. Our
findings suggest that during nocturnal and crepuscular periods, visual cues provided by resting or slow-moving fish are not
alone sufficient to attract gnathiids, while olfactory cues alone are. The traps designed for this study offer a new method
of sampling free-living gnathiid isopods. 相似文献
9.
Coatis (Nasua spp.), gregarious, omnivorous carnivores that range in forests from the southwestern USA to south America, dispatch millipedes
by rolling them on the ground using rapid, alternating movements of their forepaws. Prey rolling of millipedes is thought
to stimulate the depletion of their defensive secretions and to wipe off secretions before millipedes are consumed. We report
that prey-rolling behavior in Nasua spp. is elicited by 1,4-benzoquinone; 2-methyl-1,4-benzoquinone; and 2-methoxy-3-methyl-1,4-benzoquinone, the chief components
of the defensive secretions of julidan, spirobolidan, and spirostreptidan millipedes. Chemicals elaborated for defense sometimes
evolutionarily “backfire,” providing cues to predators on the presence or identity of prey. The elicitation of prey-rolling
behavior in Nasua spp. by benzoquinones illustrates this effect for millipedes (and possibly other arthropods) that defensively discharge these
compounds. 相似文献
10.
Paul J. Weldon Yasmin J. Cardoza Robert K. Vander Meer W. Clint Hoffmann John W. Daly Thomas F. Spande 《Die Naturwissenschaften》2013,100(2):185-192
Nearly 500 alkaloids, representing over 20 structural classes, have been identified from the skin of neotropical poison frogs (Dendrobatidae). These cutaneous compounds, which are derived from arthropod prey of the frogs, generally are believed to deter predators. We tested the red imported fire ant (Solenopsis invicta) for toxicosis following contact with 20 alkaloids (12 structural classes) identified from dendrobatids or other anurans. Individual ants forced to contact the dried residues of 13 compounds exhibited convulsions and/or reduced ambulation. We estimated the cutaneous concentrations of several compounds based on their reported recoveries from skin extracts of free-ranging frogs and our measurements of the skin surface areas of museum specimens. Pumiliotoxin 251D exhibited contact toxicity below its estimated cutaneous concentration in the Ecuadorian frog, Epipedobates anthonyi, an observation consistent with the hypothesized role of this compound in anuran chemical defense. Our results and those of a previous study of mosquitoes indicate that some anuran skin compounds function defensively as contact toxins against arthropods, permeating their exoskeleton. 相似文献