Tinea Pellionella Research Articles

Développement larvaire et bilan d'utilisation d'énergie en fonction de l'hygrométrie chez Tinea pellionella L. (Lepidoptera : Tineidae)

We studied the ability of the case-bearing clothes moth (Tinea pellionella L.) larva to develop in a dry environment and we examined the strategy developed by this species to survive under dry conditions. In a dry environment the larval development was characterized by a high level of mortality and a reduced growth rate. The weight of the fully grown larva was twice as low at 5% relative humidity (RH) as at 95% RH. The consumption index was higher at 5% RH than at 95% RH but the oxygen consumption per day was unchanged. For the same quantity of food ingested, oxygen consumption was higher at 5% RH than at 95% RH. The digestibility of ingested food was low under dry conditions and the efficiency with which digested food was converted to body substance was much reduced at 5% RH. A large proportion of digested food was utilized by the larva for water production. In spite of a high energy extraction efficiency, the larval production was greatly reduced in a dry medium because of the low efficiency of storage of metabolizable energy. In a dry environment the amount of energy required for water production is so large (24% of ingested energy) that it does not allow optimal development; only survival is possible under these conditions.

Studies in Mothproofing: Part III: Patterns of Damage Caused in Moothproofed Woolen Fabrics by Two Species of Clothes Moth

The efficacy of dieldrin (1–0.0009% on fabrics), Mitin (16–0.156%), and Eulan U33 (6–0.0058%) was tested with 30-day-old larvae of Tinea pellionella (L.) and 25-day-old larvae of Tineola bisselliella (Hum.) at 25° C and 75% RH, raised on dried fish and yeast. With higher concentrations of the proofing agents, all larvae died within one or two weeks, and the damage was 0.05–4 mg per 10 larvae, depending on the concentration. With less proofing agent, the damage in the first week (20–35 mg) was increased in the next three weeks to a total of 130–200% of the first amount, the mortality was low, and pupation began from the third week. At concentrations between these, the damage was 7–10 mg and the mortality was 100%. All three mothproofing agents were somewhat more effective against Tineola than Tinea. As compared with the Attagenus larvae, these clothes moths are slightly less susceptible to dieldrin, more susceptible to Eulan U33, and show about the same susceptibility to Mitin.

Studies in Mothproofing: Part II: Feeding Damage to Several Kinds of Fibers by the Larvae of Two Species of Clothes Moth, with a Note on Their Life Histories

Under natural conditions, Tinea pellionella has two generations (one of 70 and one of 300 days) a year, and Tineola bisselliella has three generations (45, 45, and 250 days) a year. At 25° C Tinea produces about six generations a year of about 55 days each with feeding periods of about 42 days, and Tineola produces eight generations of about 42 days each with feeding periods of about 32 days. Fed on a combination of dried fish or wool with yeast, Tinea larvae develop in about 56 days and Tineola in about 40 days. With dried fish or yeast alone, a longer developmental period is required. Fed with wool alone, all larvae die before long. In both species of moth, the greatest damage is done to wool between the 25th and 30th day after hatching and the amount of damage done by both species is comparable. A medium amount of damage is done to regenerated cellulose fibers and unscoured silk. The damage to scoured silk and chemical fibers is slight. Damage to staple and filament is greater than that to cloth. Especially in Tineola is this last factor related to case building activity of the larvae.

Observations on the ecology of the cloths moths Tineola bisselliella (Humm) and Tinea pellionella L in a bulk wool store.

Observations on the behaviour and abundance of Tineola bisselliella and Tinea pellionella were made during 1942 and 1943 in a Brisbane wool store which remained relatively undisturbed for more than three years. The store contained c. 10,000 strongly compressed. jute-covered "double dumps" of low-grade, greasy wool, stacked in large bays separated by passages. Microclimatic conditions were more equable than in the open and very favourable to the moths. Substantial vertical gradients in temperature and relative humidity resulted from insolation of the roof, but there was little horizontal differentiation. The wool tended to buffer fluctuations of these elements, both in the free air spaces and, still more, within the dumps. Larvae of Tinea were confined to loose wool protruding through breaches in the jute pack. Tineola occurred both there and within the surface 2 in. of the compressed wool under the pack. By 1943 there was estimated to be an average of c. 50 well-grown larvae per dump. Adult moths could always be seen sitting or running on the dumps throughout the stacks. The moth populations were studied by sampling with tanglefoot traps in the passages and stacks. Both species had a flight period around dusk, about half the 24-hr catch being made during the 3 hr after sunset. The peak fell earlier on cool evenings. A regression of activity on mean flight period temperature was established, a rise from 65 to 80�F doubling the catch. Females rarely fly: they normally constituted only c. 0.3 per cent, of the catch, although the sex ratio in the population as a whole was probably about 23 : 19 for Tineola and 13 : 49 for Tinea. The density of moths in flight was approximately equal in stacks and passages at a, given level, but usually increased with height. By correcting the daily catches for the effect of temperature on activity, plots of adult abundanoe against time were constructed. The two species fluctuated in almost identical fashion. Numbers were low in winter, high in spring and summer, with an indication of two to three generations per annum. From the beginning of 1943 a great decline in abundance set in, the peak for that year being a small fraction of that for 1942. The braconid Apanteles carpatus, a parasite of both moths, was also taken on the traps. It had a flight period at about the time of the daily temperature maximum. A regression of activity on temperature showed a near-quadrupling of the catch for a rise from 70 to 85�F. A plot of adult abundance was derived as for the moths. It showed a single seasonal peak falling after the moth peaks. Several overlapping generations are postulated. The abundance ratio of Apanteles to moths rose steadily from spring to autumn in each year, but showed close agreement for corresponding seasons of the two years: there is no reason to ascribe the 1943 decline in moth numbers to the parasite. A spider, Uloborus geniculatus, became very abundant during 1943 and is believed to have been responsible for the decline of the moths, which represented its main source of food. Over the relevant period the percentage of female moths in the catch increased 40-fold, presumably as a result of the differential removal of the active males by the spider. It is calculated that in this way the number of males was reduced, by November 1943, to about 1/45 of what it would otherwise have been. The spider probably also caught adult Apanteles. It is concluded that, apart from effects of the introduction of additional species, the moths and spiders would ultimately establish some sort of equilibrium, probably at a rather low level of density. The factors favouring Uloborus in its limiting role are discussed.

Studies on the Bionomics of the Case-bearing Clothes Moth, Tinea pellionella (L.)

Tinea pellionella (L.), commonly known as the Case-bearing Clothes Moth or Fur Moth, is of world-wide distribution and is of considerable economic importance. It has been recorded on a variety of substances, particularly those of a keratinous nature. In India, it has been found as an important pest of woollen textiles. Its life-history and habits have been systematically investigated at different levels of temperature and humidity.The incubation period is 4 to 5, 5, 6 to 7 and 6 to 7 days at 21·5, 25, 30 and 32·5°C., respectively. Temperatures higher than 32·5°C. have been found lethal to eggs. Humidity has no effect on the incubation period. Percentage viability of eggs is greater at lower than at higher temperatures.Both temperature and humidity have been found to influence the larval development and the number of larval instars. Irrespective of temperature, higher humidities favour shorter larval development and the shortest larval period is at 25°C. and 90 per cent. R.H.Woollen materials impregnated with yeast are more suited for the larval development than those not so treated. Larvae do not exhibit colour preference. Woollen fabrics dyed with Cloth fast orange G 4 per cent, manufactured by “ Ciba ”, however, inhibit the growth of freshly hatched larvae.The behaviour of the larvae to direct sunlight has been studied. The rôle of (a) diffused light alternated with darkness, (b) darkness, (c) temperature and (d) humidity on the extent of damage caused by the larvae has been investigated. Under the conditions of the experiments, the amount of damage in continuous darkness was significantly greater than in alternating light and darkness, and that at 90 per cent. R.H. significantly greater than at 30 per cent., but there was no significant difference in the amount of damage at 27·5° and 32·5°C., respectively, and 90 per cent. R.H.The mode of pupation has been described. The pupal period has been studied and found.to occupy 18 ± 0·4, 10·3 ± 0·16 and 10·3 ± 0·33 days at 21·5, 25 and 30°C. and 90 per cent. R.H., respectively. Humidity has no effect on this period.The effect of temperature and humidity on (a) the preoviposition, oviposition and postoviposition periods and (b) number of eggs laid by a female has been studied. The life-span of the male and female, the relationship between the weight of the female at emergence and fecundity (which was highly significant) on the one hand and length of life (which was not significant) on the other has also been investigated. Sex ratio between females and males has been found to be 2·6:1. Three to four generations in a year have been recorded at 26 ± 8·0°C. and 82 ± 10 per cent. R.H. when the larvae are fed on woollen fabrics impregnated with yeast.

Chremylus Rubiginosus (Nees.), a Braconid Parasite of the Casemaking Clothes Moth

In October, 1931, several specimens of the hymenopterous parasite of the family Braconidae were taken by the writer from larvae of the casemaking clothes moth, Tinea pellionella (L.), that were collected from a wool warehouse in Columbus, Ohio. The parasites were identified by C. F. W. Muesebeck, of the Bureau of Entomology and Plant Quarantine, as Chremylus rubiginosus (Nees.).

Clothes Moths and their Control

A MONG entomologists there are well known to be two very common moths the larvae of which are destructive to fabrics; namely, the case-making clothes moth (Tinea pellionella L.) and the webbing clothes moth (Tineola biselliela Hum.); the tapestry moth (Trichophaga tapetzella L.) is much less frequent but is occasionally destructive. In the case-making clothes moth, the larva makes a portable habitation out of its silk, together with fragments of the material upon which it feeds. It withdraws completely into the case when resting, but when feeding or moving it protrudes its head and foremost body-segments. Pupation also takes place within the case, which is sealed up and anchored to the fabric or other object. The webbing clothes moth is the most abundant species of the three; its larva does not construct a portable case, but spins silken tunnels wherever it crawls over the material which it is consuming. When fully fed it constructs a silken cocoon intermixed with particles of fabric and excrement; this pupal shelter, therefore, is quite different from that of the species previously mentioned. In the rarer tapestry moth the larva constructs silk-lined burrows through the substance of the material which it infests.