Defensive Fluid Research Articles

Mimicry: imitative depiction of discharged defensive secretion on carapace of an opilionid

The opilionid, Parampheres ronae, has a pair of orange markings on its carapace at a location where some other opilionids discharge yellowish, quinone-containing defensive fluid. P. ronae itself produces a defensive secretion, but the fluid is quinone-free and nearly translucent. We suggest that the orange markings in P. ronae are aposematic in the sense that they are imitative of the glandular emissions of quinone-producing opilionids.

Chemical defense of giant springtailTetrodontophora bielanensis (Waga) (Insecta: Collembola)

The giant springtail,Tetrodontophora bielanensis (Waga), is characterized by integumental openings (pseudocells) from which small droplets of a sticky defensive fluid are secreted after molestation. The secretion originates initially from secretory cells below the pseudocellae; subsequent irritations result in release of hemolymph, which was identified by both chemical and microscopical methods as well as by scanning electron microscopy. Bioassays with topically treated ground beetlesNebria brevicollis showed that the pseudocellular fluid evokes a total disorientation and cleansing behavior of the beetle. The main constituents were identified as the following pyridopyrazines: 2,3-dimethoxpyrido[2,3-b]pyrazine (1), 3-isopropyl-2-methoxypyrido[2,3-b]pyrazine (2), and 2-methoxy-4H-pyrido[2,3-b]pyrazine-3-one (3). These alkaloids are mainly present in the pseudocellar fluids of female and male springtails but are absent in their food or feces. Minor amounts are found in the hemolymph of adults, while larvae contain traces of2 only. All compounds were synthesized and tested for activity. In natural concentrations, the synthetic alkaloids elicited the same effects from the ground beetles as the pseudocellar fluid.

Inhibitory action of the defensive discharge of the grasshopper, Poecilocerus pictus, on certain enzymes in the lizard, Calotes nemoricola.

Administration of the defensive secretion of the grasshopper, Poecilocerus pictus inhibited acetyl-cholinesterase (AChE) and adenosine triphosphatases (ATPases) in the brain and muscle tissues of the garden lizard, Calotes nemoricola. The inhibition was gradual, continuous and irreversible with lethal doses of the defensive secretion, whereas the inhibition observed with sublethal doses was followed by an increase towards control levels within 24 h after injection. In vitro application of defensive secretion also showed concentration-dependent inhibition in the activity of AChE and ATPases in the tissue homogenates. Inhibition in AChE activity might be a factor for the observed mortality is the defensive fluid-treated lizards. Since the cardenolides are known to inhibit the activity of ATPases, the inhibition in the activity of ATPases observed in the present study suggests the presence of cardenolides in the defensive fluid of P. pictus.

Defensive use of an acquired substance (carminic acid) by predaceous insect larvae.

Larvae of two insects, a coccinellid beetle (Hyperaspis trifurcata) and a chamaemyiid fly (Leucopis sp.), feed on cochineal insects and appropriate their prey's defensive chemical, carminic acid, for protective purposes of their own. H. trifurcata discharges the chemical with droplets of blood (hemolymph) that it emits when disturbed; Leucopis sp. ejects the compound with rectal fluid. Ants are thwarted by these defenses, which are compared with the previously-described defense of a pyralid caterpillar (Laetilia coccidivora) that disgorges carminic acid-laden crop fluid. The defensive fluid of all three larvae contains carminic acid at concentrations spanning a range (0.2-6.2%) proven deterrent to ants. Many insects are known to appropriate defensive substances from plants. Insects that acquire defensive chemicals from animal sources may be relatively rare.

Chemical defense of a primitive Australian bombardier beetle (Carabidae):Mystropomus regularis

The Australian bombardier beetle,Mystropomus regularis, sprays a mixture of quinones (1,4-benzoquinone, 2-methyl-1,4-benzoquinone, 2-ethyl-1,4-benzoquinone) and hydrocarbons (principallyn-pentadecane). The defensive fluid ist generated explosively in two-chambered glands, and is ejected audibly and hot (maximal recorded temperature = 59°C).Mystropomus is a member of the paussoid lineage of bombardiers. In common with other members of the group, it has a pair of elytral flanges (flanges of Coanda), associated with the gland openings, that serve as launching guides for anteriorly-aimed ejections of spray. It is argued thatMystropomus may be the least derived of flanged paussoids, and the closest living relative of the most primitive of extant bombardiers (Metriini).

The chemical nature of the adult defensive secretion of the tip wilter, Elasmopoda valga

The chemical composition of the defensive fluid secreted by adult Elasmopoda valga (Hemiptera: Coreidae) was determined by gas chromatography-mass spectrometry using a thick film glass capillary column. The secretion collected from individual insects was found to contain the aldehydes, ethanal, butanal, hexanal and (E)-2- hexenal , the carboxylic acids, ethanoic acid, butanoic acid and hexanoic acid, the alcohols, butanol and hexanol, the esters, butyl ethanoate, hexyl ethanoate, octyl ethanoate, butyl butanoate, hexyl butanoate and hexyl hexanoate, i.e. only straight-chain compounds, as well as traces of water in varying proportions. The detection and quantitative determination of these compounds in the secretion are described and their function discussed.

Cuticular cavities: Storage chambers for cyanoglucoside-containing defensive secretions in larvae of a zygaenid moth

As a defensive reaction against predators the larvae of Zygaena trifolii Esper, 1783, release highly viscous fluid droplets out of cuticular cavities. The fluid appears on the cuticular surface upon contraction of the irritated segments, with no specialized muscles being involved. Two morphologically different types of cavities have been found: the larger ones are located beneath pigment spots, the smaller ones occupy the remaining surface except in the ventral region. Both types have complicated cuticular opening structures. The defensive fluid contains the cyanoglucosides linamarin and lotaustralin, the amino acid β-cyano-L-alanine, proteins and water. Although a considerable amount of fluid (3–6 μ1 per sixth-instar larva) is stored in the cuticle, fine structural examinations of the epidermis do not show any specific cells or cell areas with morphological adaptations for secretion. Further, there do not exist any major cytological differences between the cells below the cavities and in the ventral region, where those cavities are absent.

Defensive secretion of the pill millipedeGlomeris marginata. I. Fluid production and storage

AdultGlomeris marginata reloaded glandular defensive fluid slowly and fairly constantly at 15 °C for 100 days after being milked to depletion. Female millipedes produced more sticky exudate than males, but the two sexes stored secretion at approximately the same absolute rate, 12 μg/individual/day. Hence, males, which weighed one third as much as females, accumulated disproportionately more secretion. MaleGlomeris in the reloading treatments after 75 days yielded as much exudate as controls, millipedes given 100 days to supplement their field reserves, whereas experimental females always produced less secretion than controls. Projections from these data suggest that adultGlomeris, regardless of sex, require more than 4 months to replenish their defensive reserves after completely discharging them in an attack.

A review of the Nasutitermitinae (Isoptera: Termitidae) from India

Abstract Members of the subfamily Nasutitermitinae are widely distributed throughout the tropics. This subfamily is the highest evolved one, and is also the largest subfamily in the Order Isoptera. The direction of evolutionary advancement in the subfamily Nasutitermitinae is the gradual reduction of the mandibles of the soldier caste accompanied by progressive increase in rostrum or nasus. A gland secreting defensive fluid opens at the tip of the rostrum and the secretion is forcefully squirted out at the enemy. The most primitive living genus in the subfamily is Syntermes which is Neotropical. Other primitive genera with well developed mandibles also occur in the same region. The morphological characters found useful in the classification and phylogenetic relationship among various genera are: (i) gross structure of imago-worker mandibles, (ii) length of postclypeus in relation to its width in imago, (iii) degree of degeneration of mandibles and presence or absence of lateral spinous process (apical poi...

A thermodynamic perturbation theory study of a defense fluid of polar and polarizable hard spheres

This paper reports some thermodynamic perturbation calculations for a dense polarizable dipolar fluid. The polarizability is defined by the tensor α and we have obtained lower bounds for the contributions of the induced interactions to the free energy for anisotropies, α zz /α xx , ranging from 0 to ∞. These contributions are found to be quite large and strongly dependent on anisotropy. We examine the range of validity of the “mean polarizability” and “pairwise additivity” assumptions, and both approximations are found to be good only for very nearly isotropic polarizability.

Acid Content of Scent Fluid fromAcanthocephala femorata, A. declivis, andA. granulosa(Hemiptera: Coreidae)

The major component of the defensive scent fluids from the true bugs Acanthocephala femorata (F.), A. granulosa (Dallas), and A. declivis (Say) has been found to be trans-2-hexenal (Blum et al. 1961, McCullough 1967). An acid, present in quantities small enough to elude detection by some procedures, also has been found in the fluid of all 3 species by microtitrimetry with 0.032 N NaOH to phenolphthalein end point, as Table 1 summarizes.

Particles present in the haemolymph and defensive secretions of insects.

ABSTRACT Defensive fluids obtained from the Garden Tiger, Scarlet Tiger and Burnet Moths and from the Monarch Butterfly and the Seven-Spot Ladybird Beetle, haemolymphs taken from the wasp, the Burying Beetle and the Rat Flea, and fluids from the eggs of the Garden Tiger, Gypsy Moth and Oak Eggar Moth were examined in the electron microscope after negative staining. Except for the ladybird all the defensive fluids, haemolymphs and egg fluids contained particles 100–150 Å across which frequently had rectangular or square outlines. In some species the particles were occasionally arranged in groups of 2 and 4 and in the egg fluid of the Garden Tiger they were arranged in rows which were aligned side by side to form strands of considerable length. The particles are believed to be protein. They correspond in size to the 16 s component of the haemocyanins of Limulus and Homarus and the protein particles found in Calliphora by other workers.

The ultrastructure of the osmeterium and the nature of its secretion in Papilio larvae (lepidoptera)

Two main cell types constitute the defensive osmeterium gland of Papilio larvae. Ellipsoid gland cells have an extensively infolded basal plasma membrane, abundant ribosomes and whorls of smooth endoplasmic reticulum. The apical plasma membrane bears long microvilli extending into a mass of granular material containing electron-lucid cavities. Tangential slits occur in the epicuticle. Tubular arm cells contain heterogeneous, electron-dense inclusions, extensively-branched nuclei and large mitochondria sometimes distended with electron-dense material. The apical plasma membrane bears short microvilli. The inner, dense epicuticle forms a complex ramifying system. The two-phase defensive fluid consists mainly of water, 2-methyl propionic acid, and 2-methyl butyric acid.

Structure and protective devices of the egg of the mosquito Culex pipiens.

Abstract The structure and function of the egg shell of Culex pipiens L. is described. The outer layer of the shell consists of two sheets that hold a film of air between them. The film of air functions as a plastron when the egg is submerged in water. The outer sheet is an open hydrofuge network except near the anterior pole. Single eggs and rafts of eggs distort the surface film in different ways, and differences in their behaviour can be accounted for by differences in the way they make use of the surface tension of the water. The egg is protectively coloured: it is dark above and pale beneath. The pale colour of the under-surface is produced by light reflected from a water-air interface. The reflecting surface beneath erect eggs is on the anterior cup. The reflecting surface beneath eggs floating on their sides is the plastron water-air interface. On the posterior pole of each egg there is normally a drop of liquid. This liquid is shown to be a defensive fluid in experiments with two species of ants, which are natural enemies of the eggs. The defensive fluid is of maternal origin. It is kept wetted by water translocated from the anterior pole in contact with the water through the substance of the outer layer of chorion.

Quantitative Determination of Trans-2-Hexenal in the Defensive Scent Fluid of Acanthocephala declivis and A. granulosa (Hemiptera: Coreidae)

Previous work (Blum 1961, McCullough 1966) indicated the presence of trans-2-hexenal in the defensive scent fluid of 2 coreids, Acanthocephala femorata (F.) and A. granulosa (Dallas), but no amounts or percentages were reported.

Feeding Habits of Calosoma scrutator in Captivity (Coleoptera: Carabidae)

During the investigation of the defensive odorous fluid emitted by various ground beetles, I established a colony of Calosoma scrutator (F.) caterpillar hunters. Whenever available, grub worms and caterpillars were fed to the colony, but the hot, dry weather of late spring and summer soon eliminated the source of supply. Other food items were then tried with varying degrees of acceptance. Earthworms repelled the beetles and mealworms were eaten only with reluctance. Chopped liver was readily taken at first, but after several feedings the appeal diminished. Gidaspow (1959) described similar results with beef. I then tried several varieties of fresh fruit: apples, grapes, watermelon, bananas, and cantaloup. Because of the ready availability and the suitable texture, bananas were the fruit of choice, although all the varieties mentioned were accepted, especially when the beetles were thirsty. To check the nutritional value of bananas, 2 of the beetles (1 of each sex) were separated from the colony, fed bananas almost exclusively and were weighed periodically. Over a 206-day period, both beetles gained weight, as shown in Fig. 1. The temporary decrease in the weight of the female occurred when the insect escaped from the box and remained at large for a full week. During this time no food or water was available.

Carbonyl and Acidic Compounds Produced by Acanthocephala granulosa (Hemiptera: Coreidae)

Of the several species of Acanthocephala found in the United States, only one has been previously investigated for the chemistry of the odorous defensive fluid. Blum et al. (1961) reported the presence of trans-2-hexenal in the fluid ejected by A. femorata (F.).

Defense Mechanisms of Arthropods. III. Secretion of 2-Hexenal by Adults of the Cockroach Cutilia soror (Brunner)1

Adults of this cockroach, when disturbed, eject a defensive fluid consisting of 2-hexenal. This chemical defense mechanism is similar in every major respect to that already known from another cockroach, Eurycotis floridana (Walker).