Non-pollinating Yucca Moth
Scientific Name: Tegeticula corruptrix
Taxonomy Group: Arthropods
Last COSEWIC Assessment: May 2013
Last COSEWIC Designation: Endangered
SARA Status: Schedule 1, Endangered
Image of Non-pollinating Yucca Moth
The Non-pollinating Yucca Moth is a small white moth with a wingspan of 22.5 to 35.0 mm. Females are slightly larger than males. The forewings and hindwings are white dorsally and mostly brown on the ventral surface. The head has white scales, and there is no evidence of tentacles on the maxillary palp (mouth parts used to catch and swallow food). The antennae are approximately half the length of the forewing. The thorax has white scales and the legs are amber. The abdomen is tan on the dorsal side and white ventrally. Adults are usually observed within the flowers of their host plant, soapweed (a species of yucca), late in the flowering season. They are also observed on foliage or dried flower heads. In Canada, this small moth can be confused with two other white moths that are also found within soapweed flowers, the yucca moth and the five-spotted bogus yucca moth. The Non-pollinating Yucca Moth can be distinguished from the other two species mainly by its relatively larger size and the absence of small black dots on its wings.
Distribution and Population
The Non-pollinating Yucca Moth has been reported in yucca populations from Mexico and southern Texas north to Alberta and from California east to Nebraska. In Canada, the only sustainable population of this moth exists in a soapweed population along the Lost River, in Onefour, southeastern Alberta. There is a second Alberta population along the Milk River, on the Pinhorn Grazing Reserve, in which only a single Non-pollinating Yucca Moth individual has been recorded. It is possible that the species exists in other small transplanted patches of soapweed near Medicine Hat, Alberta, and Fox Valley, Saskatchewan, or in a few presumably transplanted plants near Rockglen, Saskatchewan. Numbers of Non-pollinating Yucca Moths fluctuate greatly between years and between populations, and the moths are difficult to count as adults. The available indices of moth activity at Onefour from 1999 to 2003 are insufficient to detect population decline or trends in abundance. Only a single individual was observed in the Pinhorn population between 1998 and 2003. This population appears to have all but disappeared, undoubtedly as a result of repeated grazing of soapweed by mule deer. The survival of the Non-pollinating Yucca Moth is entirely dependent on the obligate mutualism between its host plant and the plant’s pollinator, the yucca moth. The Non-pollinating Yucca Moth requires soapweed fruit for reproduction and as food for the caterpillars. Consequently, factors influencing the survival of either soapweed or the yucca moth will also affect the Non-pollinating Yucca Moth.
In Canada, soapweed populations inhabited by Non-pollinating Yucca Moths occupy south-facing, sparsely vegetated and well-drained slopes protected from prevailing winds. In general, these slopes are also occupied by sparse populations of prickly pear cactus and silver sagebrush. This habitat is restricted to a dry region characterized by large daily and seasonal fluctuations in temperature, low precipitation, hot summers, and high rates of evaporation exacerbated by a high average wind speed. In Canada, the Non-pollinating Yucca Moth uses only soapweed as the host plant for the eggs and as food for the caterpillars. In the United States, soapweed and several other yucca species serve as host plants.
Unlike yucca moths, Non-pollinating Yucca Moths do not pollinate their host plant (hence the name “non-pollinating”). Instead, Non-pollinating Yucca Moths are obligate seed predators of yuccas. The females of this moth lay their eggs only in early-stage yucca fruit. After hatching, the caterpillars feed only on yucca seeds. In late summer, the caterpillars chew their way out of the fruit and burrow into the soil, where they build a cocoon and enter diapause. They remain in this stage for up to several years before emerging from the soil as adult moths. In Alberta, adult moths emerge between early July and September. At nightfall, they gather and mate in late-blooming soapweed flowers or on soapweed stems and leaves. Finally, survival of the Non-pollinating Yucca Moth depends on the obligate mutual assistance relationship, called “mutualism,” between soapweed and the pollinating yucca moth. Without this moth pollinating its flowers, soapweed cannot produce fruit. Since the Non-pollinating Yucca Moth needs soapweed fruit on which to lay its eggs and for food for the caterpillars, the beneficial interaction between its host plant and the plant’s pollinator must be in place in order for the non-pollinating species to reproduce.
Abundance of the Non-pollinating Yucca Moth is restricted by the number of soapweed fruit and seeds produced. Consequently, any factor that threatens the host plant or the plant’s pollinator, the yucca moth, will also adversely affect the Non-pollinating Yucca Moth. The most serious current threat to the Non-pollinating Yucca Moth is the high level of consumption of soapweed by mule deer and pronghorn antelope. These herbivores eat the flowers and fruit. The grazing greatly reduces the number of fruit produced and therefore the number of seeds produced, with the result that the reproductive success of soapweed, the yucca moth and the Non-pollinating Yucca Moth are all reduced. In addition to reducing the availability of egg-laying sites for the moth, grazing on flowers and fruit also results in the direct mortality of any caterpillars within the fruit. In addition, all moth eggs within the flowers or fruit that are eaten are destroyed. Repeated bouts of intense grazing are thought to have resulted in the near extirpation of the yucca moth from the Pinhorn population of soapweed. Other possible threats to the Non-pollinating Yucca Moth include destruction of its host plant by off-road vehicle traffic and the collection of soapweed for horticultural and medicinal uses.
Federal ProtectionThe Non-pollinating Yucca Moth is protected under the federal Species at Risk Act (SARA). More information about SARA, including how it protects individual species, is available in the Species at Risk Act: A Guide.
In Alberta, the Non-pollinating Yucca Moth is not protected under any provincial statute.
Provincial and Territorial Protection
PLEASE NOTE: Not all COSEWIC reports are currently available on the SARA Public Registry. Most of the reports not yet available are status reports for species assessed by COSEWIC prior to May 2002. Other COSEWIC reports not yet available may include those species assessed as Extinct, Data Deficient or Not at Risk. In the meantime, they are available on request from the COSEWIC Secretariat.
11 record(s) found.
- COSEWIC Status Reports (2 record(s) found.)
- COSEWIC Assessments (1 record(s) found.)
- Response Statements (2 record(s) found.)
- Orders (2 record(s) found.)
- COSEWIC Annual Reports (2 record(s) found.)
- Consultation Documents (1 record(s) found.)
- Recovery Document Posting Plans (1 record(s) found.)
COSEWIC Status Reports
COSEWIC Assessment and Status Report on the Yucca Moth Tegeticula yuccasella, Non-pollinating Yucca Moth Tegeticula corruptrix and the Five-spotted Bogus Yucca Moth Prodoxus quinquepunctellus in Canada (2013)Yucca Moths are small white moths with an 18-27.5 mm wingspan. They have specialized maxillary tentacles used to handle the pollen of Yucca spp., with which they engage in an obligate pollination-seed predation mutualism.
COSEWIC Annual Reports
COSEWIC Annual Report - 2006 (2006)2006 Annual Report to the The Minister of the Environment and the Canadian Endangered Species Conservation Council (CESCC) from the Committee on the Status of Endangered Wildlife in Canada.
Recovery Document Posting Plans
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