Acanthocephala (Acanthocephala) declivis Say

Acanthocephala (Acanthocephala) declivis (Say)

(Figs. 1, 5, 6, 13)

Rhinchus declivis Say, 1832, Ins. La., p. 10.

Acanthocephala (Acanthocephala) declivis: Stål, 1870, K. Svens. Vet.-Akad. Handl. 9(1): 150.

Diagnosis. Length: 28–34 mm. This species can be recognized by the humeral angles of the pronotum, which are broadly rounded and strongly extended laterally. The metatibial expansions are broadly dilated for most of their length, ending abruptly near the apex.

Distribution. AL, AR, AZ, FL, GA, IL, KY, LA, MO, NC, NM, SC, TX, VA (El Salvador, Greater Antilles, Guatemala, Mexico [Durango, Nuevo Leon, Puebla, San Luis Potosi, Tamaulipas])

Discussion. Little is known about the biology of this species. It has been collected from December through August in Florida (Blatchley 1926, Baranowski & Slater 1986). Froeschner (1942) reported two specimens from Missouri, one collected in St. Louis on 26 August 1938, the other in Columbia on 17 November 1941, the latter having been "freshly smashed on a sidewalk." Hoffman (1992) reported it from Virginia.

Published information on plant associations is limited. Palmer (1987) conducted a survey of the phytophagous insect fauna associated with Baccharis neglecta Britton (Rooseveltweed, false willow) and B. halimifolia Linnaeus (eastern baccharis, groundseltree) in Texas, Louisiana, and northern Mexico. He reported A. declivis as a rare ectophagous species on B. neglecta without indicating a specific location but, apparently, this was observed in Texas. Also, Blatchley (1926) reported beating specimens from foliage of Persea borbonia (Linnaeus) (red bay) along margins of wet hammocks. Eberhard (1998) stated that males of A. declivis guatemalena Distant battled other males at feeding and mating sites, primarily on trunks and branches of Cordia elaeagroidei (probably a misspelling of Cordia elaeagnoides A. DeCandolle) (Boraginaceae) in Jalisco, Mexico, this behavior being similar to that observed for A. femorata (Mitchell 1980).

1. All body lengths taken from Torre-Bueno (1941).

2. Geographic distributions from Froeschner (1988) unless noted otherwise (all new records appear in bold). 3. A substantial amount of host plant and life cycle information is provided by Paula Levin Mitchell from her unpublished field notes and from observations given to her by T. P. Friedlander (see Acknowledgments). Unless noted otherwise, all data were recorded in Austin, TX, at the Brackenridge Field Laboratory of the University of Texas. Observations from Friedlander are identified as PLM/TPF. Data gathered elsewhere are noted specifically in the text.

PLM (unpublished data) provides the following information: This species was found with A. terminalis on Celtis laevigata Willdenow (sugarberry) (1978) in "mixed sex aggregations with adults observed feeding on sap through the bark" on 29 March (PLM/TPF). It also was found on Baccharis neglecta (1976) (4 adults, February– March, November) from the same locality, but no nymphs or feeding was observed.

CSB here reports adults of this species from Prosopis (mesquite) (TX), Gossypium hirsutum L (cotton) (GA), and Glycine max (Linnaeus), (soybean) (GA). RWS notes a specimen in the Enns Entomology Museum collected at UV Light (TX, Lake Mathis).

Arnaud (1978) reported that A. declivis is parasitized by the tachinid fly Trichopoda pennipes (Fabricius).

Recently (2009), three specimens (2 adults, 1 5th instar) were collected on the Southern Illinois University- Carbondale (SIU) campus and one (an adult) on the University of Illinois at Urbana-Champaign campus. The label information is given below with additional information in parentheses:

Illinois: Jackson Co., SIU campus, 23 Sept. 2009, K. S. Delahunt, Coll. (1 adult); 5 Nov. 2009, V. Begosian, Coll. (1 adult); Thompson Woods, 26 September 2009, Erin Doody, Coll. (1 5th instar) (specimens deposited in SIU Entomology Collection) (SIUEC). Champaign Co., nr. Illinois Natural History Survey (INHS) Annex, (University of Illinois at Urbana-Champaign campus), collected on wooden chair, J. G. Laird (Coll.) (1 adult) (specimen deposited in INHS Collection).

Taxonomic notes. Brailovsky (2006) resurrected A. alata (Burmeister) from synonymy under A. declivis, as well as described a similar new species, A. heissi Brailovsky, and stated that A. declivis occurs only in the U. S. and that Mexican and Central American records of A. declivis should be applied to A. alata. This includes several subspecies of A. declivis including A. d. guatemalena. RJP feels that, at this time, A. declivis, A. alata, and A. heissi should be considered sibling species. The removal of A. alata from synonymy requires further study.