Tegrodera erosa inornata

Blaisdell, 1918

Tegrodera erosa inornata is a of blister beetle to cismontane southern California and Baja California. It is one of three subspecies within the T. erosa , distinguished from the nominate subspecies by reduced or absent elytral markings. Like all Tegrodera , it contains in its and has been associated with livestock concerns when present in alfalfa hay. The subspecies is currently considered to be undergoing range retrenchment due to urban development.

Pronunciation

How to pronounce Tegrodera erosa inornata: //tɛˈɡroʊ̯.dɛ.rə ɛˈroʊ̯.sə iːˌnɔrˈneɪ̯.tə//

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Identification

Tegrodera erosa inornata can be distinguished from the nominate T. e. erosa by its reduced or absent elytral patterning—the name "inornata" refers to this relatively unmarked appearance. Males possess paired grooved depressions on the used during courtship to grasp female . All Tegrodera are large, robust beetles with bright coloration; when threatened, they display a "frightening attitude" by suddenly elevating the to expose brilliant red abdominal intersegmental .

Habitat

Dry valleys and hills of cismontane southern California; extends south into Baja California. Associated with open, arid environments where plants grow.

Distribution

to southern California and Baja California, Mexico. The occurs in the dry valleys and hills west of the coastal mountains (cismontane zone), with the nominate subspecies T. e. erosa occupying more northerly or interior portions of the range.

Seasonality

active primarily in late spring and early summer.

Diet

feed on Eriastrum (Polemoniaceae) as the primary plant; will also feed on alfalfa (Medicago sativa) where agriculture encroaches on natural .

Host Associations

Eriastrum - primary plantPolemoniaceae; low herbaceous annuals
Medicago sativa - secondary plantalfalfa; utilized where agriculture borders natural lands

Life Cycle

Larval unknown. Based on related , larvae are presumed to be or on provisions and immatures of soil-nesting bees.

Behavior

form large feeding and mating . Males exhibit unique courtship : facing the female, grasping her with his own, and repeatedly pulling them through his grooves where stimulatory compounds are presumably released. When threatened, performs a "frightening attitude" display involving sudden elevation of to expose red abdominal combined with rapid retreat. Occasionally observed moving in single file, a behavior contributing to the "soldier beetle" (though this name properly belongs to Cantharidae).

Ecological Role

Herbivore; feeding on native annuals and agricultural crops. Potential role in pollination of plants unstudied. to vertebrate via provides chemical defense.

Human Relevance

Poses a threat to livestock when present in alfalfa hay, as in is toxic to mammals, particularly horses. The is experiencing loss and range retrenchment due to urban development in southern California, raising conservation concerns for this .

Similar Taxa

Tegrodera erosa erosaNominate with more pronounced elytral markings; occurs in more northerly or interior portions of the range
Tegrodera latecinctaThird in , distinguished by elytral banding pattern; occurs in Antelope and Owens valleys to the north
Tegrodera alogaSister occurring in Sonoran Desert of western Arizona, extreme southeastern California, and northwestern Sonora; distinguished by color pattern and distribution

More Details

Taxonomic history

Described by Blaisdell in 1918 as a distinct form based on reduced elytral markings. The Tegrodera erosa has been subject to ongoing taxonomic refinement by J. D. Pinto and colleagues.

Conservation status

Likely undergoing considerable range retrenchment in southern California due to unprecedented urban development of its , per observations by J. D. Pinto (2010).

Chemical defense

Like most meloids tested, Tegrodera contains , a terpenoid compound toxic to mammals that serves as a deterrent.