(DRAFT) - Taxonomy
Species NAUCORID, ASH MEADOWS
Species Id ESIS501012
Date 13 MAR 96
TAXONOMY
NAME - NAUCORID, ASH MEADOWS
OTHER COMMON NAMES - NAUCORID, ASH MEADOWS; BUG, ASH MEADOWS; NAUCORID and POINT-OF-ROCKS SPRINGS
ELEMENT CODE -
CATEGORY - Terrestrial Insects
PHYLUM AND SUBPHYLUM - ARTHROPODA,
CLASS AND SUBCLASS - INSECTA,
ORDER AND SUBORDER - HEMIPTERA,
FAMILY AND SUBFAMILY - NAUCORIDAE,
GENUS AND SUBGENUS - AMBRYSUS,
SPECIES AND SSP - AMARGOSUS,
SCIENTIFIC NAME - AMBRYSUS AMARGOSUS
AUTHORITY -
TAXONOMY REFERENCES -
COMMENTS ON TAXONOMY -
Ash Meadows Naucorid
Ambrysus amargosus La Rivers, 1953
KINGDOM: Animal GROUP: Insect
PHYLUM: Arthropoda CLASS: Insecta
ORDER: Hemiptera FAMILY: Naucoridae
Naucorids are oval, flattened bugs with raptorial front legs.
The middle and hindlegs are modified for swimming. The antennae are
four-segmented and usually hidden. The beak is short the ocelli are
absent, and there are no veins in the hemelytral membrane. Naucorids
lack the caudal, straplike, abdominal appendages which are
characteristic of the Belostomatidae.
Following Usinger (06), the Naucoridae is divided into eight
subfamilies containing 37 genera and about 300 species. Two of the
subfamilies, Cheirochelinae and Aphelocheirinae, occur only in the Old
World. Of the others, i.e., Potamocorinae, Laccocorinae,
Cryphocricinae, Limnocorinae, Ambrysinae, and Naucorinae only the last
four are Nearctic. Popov (07,08) proposed that the Cheirochelinae,
Laccocorinae, Limnocorinae, and Ambrysinae be reduced to tribes of the
Naucorinae, a proposition accepted by Nieser (09) and Parsons and
Hewson (10).
Taxonomy - 1 (DRAFT) - Taxonomy
Species NAUCORID, ASH MEADOWS
Species Id ESIS501012
Date 13 MAR 96
Phylogenetically, the naucorids are considered to be closest to
the Old World and South American family Helotrephidae, but naucorids
are also structurally similar to the back-swimming Notonectidae.
Ambrysus is distinguished by the deeply concave anterior pronotal
margin, the propleura produced plate-like over the posterior part of
the prosternum, and the densely pubescent venter. Of the nearly 70
species in this genus, 14 are known from the United States (04).
Ambrysus amargosus, the Ash Meadows Naucorid, is a small insect
measuring 6.0 - 6.5 mm in length by 4.0 - 4.5 mm in width, ovate when
viewed from above and strongly dorsoventrally flattened. Coloration
is predominantly dull medium brown with scattered dark yellowish
markings on the head and thorax and pale legs. Ambrysus amargosus
differs from other Ambrysus species by lateral margins of first and
second abdominal segments smooth, those of segments 3-5 minutely
serrate (best seen from below). The small male process, and shape of
the slightly asymmetrical female subgenital plate are diagnostic.
The species is flightless, with hindwings noticably shortened,
reaching only to the middle of the forth tergum. Diagnostic keys and
illustrations can be found in Menke, 1979 (04).
The species was described by Ira La Rivers in 1953 (01) from a
series of specimens taken by himself and T. Frantz at Point of Rock
Springs, Nye County, Nevada. There have been no nomenclatural
disagreements regarding this species since the original description.
The type specimens are deposited in the California Academy of Sciences
in San Francisco. Additional specimens may be found in collections at
the University of California, Berkeley; the Snow Entomological Museum,
Lawrence, Kansas; the United States National Museum, Washington, D.C.;
and the J.T. Polhemus Collection, Englewood, Colorado. La Rivers (01)
provided line drawings of the male and female genital structures and
the hind wing, but no habitus illustration of this species exists.
Other common names for this species are the Ash Meadows bug (11)
and Point-of-Rocks Springs naucorid.
Taxonomy - 2 (DRAFT) - Status
Species NAUCORID, ASH MEADOWS
Species Id ESIS501012
Date 13 MAR 96
STATUS
Coded Status
T: Federal Threatened
COMMENTS ON STATUS -
UNAPPROVED PLAN:
U.S. Fish and Wildlife Service. 1986. Recovery Plan for the
Endangered and Threatened Species of Ash Meadows, Nevada. Agency
Review Draft. U.S. Fish and Wildl. Serv., Portland, OR. 169 pp.
The primary objective of the "Recovery Plan for the Endangered
and Threatened Species of Ash Meadows, Nevada" is to reclassify the
endangered-threatened populations to non-listed status by restoring
and protecting habitat which can support viable, self-sustaining
populations. The size and extent of populations need to be determined
for most species, and the habitats of all species except the spring-
loving centaury occur within the Ash Meadows essential habitat.
Except for the Devil's Hole pupfish and Warm Springs pupfish,
reclassification may be considered when threats have been removed and
when habitats/populations have been restored for a period of ten
years to specified levels (as determined through research);
The general criteria for reclassifying/delisting the Ash Meadows
naucorid is summarized as follows:
A) protect Ash Meadows aquifer to maintain current (January 1986)
spring discharge;
B) determine historic distribution and population size by
surveying existing and potential habitats, and reviewing the
literature;
C) rehabilitate habitat to support populations throughout native
range. The extent of this habitat and size of populations to
be determined by research;
D) eliminate exotic species including vertebrates, invertebrates,
and vegetation;
E) enforce all State and Federal laws and regulations; and
F) implement a public information and education program
G) restrict any kind of collection.
83/10/13:48 FR 46590/46597 - Proposed rule
84/04/10:49 FR 14152/14153 - Reopening of comment period
85/05/20:50 FR 20777/20794 - Final Rule: Threatened w/ Crit. Hab.
Status - 1 HABITAT ASSOCIATIONS
HABITAT - AQUATIC
INLAND AQUATIC
LAND USE -
Shrub and Brush Rangeland
Streams and Canals
Nonforested Wetland
NATIONAL WETLAND INVENTORY CODES
NWI NWICLS NWIMOD NWISPEC
Riverine, upper perennial SB1
Riverine, upper perennial SB
COMMENTS ON HABITAT ASSOCIATIONS -
The Ash Meadows naucorid occurs only in the thermal outflows
of the Point of Rocks Springs in eastern-central Ash Meadows, Nevada.
The original habitat as described by La Rivers in 1953 (01) consisted
of scattered spring outflows which exited from a rocky hillside and
collected in a small pond 30 feet long by 15 feet wide, which was in
turn drained by two outlet streams. This habitat has been
substantially destroyed by the creation of several large, deep, cold
ponds where the small pond and outflow streams formerly existed; the
only portion of the habitat still remaining in a relatively natural
state is a set of very small, shallow channels draining the thermal
springs at the point where they exit from cavities in the hillside.
An examination of the locality by D.A. Polhemus in 1984 (05) found
these channels to be heavily choked with tumbleweeds and brush for
much of their length, with the insects occurring only in the short
unshaded stretches of channel immediately below the spring origins.
Significant alteration and destruction of this species' extremely
restricted habitat thus seems to have confined the species to these
few very short outflow channels below a thermal spring.
La Rivers (01) gives the following limnologic characteristics for
the habitat: pH = 7.3; CO2 = 20ppm; HCO3 = 256ppm; DO = 2.7ppm; water
temperature = 32.2 degrees C. Substrate in the channels consists of
loose rock and gravel. The streams are mostly unshaded and flow
through open desert dominated by cresote bush (Larrea divaricata) and
saltbrush (Atriplex sp). The stream flow is strong enough to keep the
bottom sand-free but too weak to move the gravel that the Ambrysi seem
most at home with (01). Environmental factors most critical to the
survival of this species are sufficient flowing water and warm water
temperature. Disruption of any portion of the remaining natural
spring habitat would have an extremely adverse impact on this species.
Habitat Associations - 1 (DRAFT) - Food Habits
Species NAUCORID, ASH MEADOWS
Species Id ESIS501012
Date 13 MAR 96
FOOD HABITS
TROPHIC LEVEL -
CARNIVORE
LIFESTAGE FOOD FOOD PART
General Arthropods
Food Habits - 1 (DRAFT) - Environment Associations
Species NAUCORID, ASH MEADOWS
Species Id ESIS501012
Date 13 MAR 96
ENVIRONMENTAL ASSOCIATIONS
G = General A = Adult
LIM = Limiting RA = Resting Adult
J = Juvenile FA = Feeding Adult
RJ = Resting Juvenile BA = Breeding Adult
FJ = Feeding Juvenile P = Pupae
L = Larvae E = Egg
RL = Resting Larvae
FL = Feeding Larvae
LIFESTAGE ENVIRONMENTAL ASSOCIATIONS
G
G Aquatic Features: Pool areas
G Aquatic Features: Springs [flowing]
Environment Associations - 1 (DRAFT) - Life History
Species NAUCORID, ASH MEADOWS
Species Id ESIS501012
Date 13 MAR 96
LIFE HISTORY
FOOD HABITS:
Nothing is known of the specific food habits of Ambrysus
amargosus, the Ash Meadows naucorid. Usinger (03) reported that other
congeneric species in the genus Ambrysus prey on various aquatic
insect larvae, and it may be assumed that this holds true for A.
amargosus as well.
HOME RANGE/TERRITORY:
Unknown.
PERIODICITY:
In Nearctic naucorids, hibernation is known only in Pelocoris
femoratus from the eastern United States. This species retreats to
the bottoms of pools and ponds where there is some depth of muck and
especially where water plants remain rooted through the winter (Uhler,
1884) (12). Other forms, including the Pelocoris found in California,
inhabit warmer regions or hot springs for the most part, and
generally hibernation is unnecessary (04).
MIGRATION PATTERNS:
Unknown.
COVER/SHELTER REQUIREMENTS:
This species requires shallow, flowing steams with beds of small
diameter gravel but free of sand (01). The species occurs in unshaded
stretches of the streams.
REPRODUCTIVE SITE REQUIREMENTS:
The reproductive biology of A. amargosus is presently unknown.
Usinger studied the biology of A. mormon in California. The creamy
white eggs are glued to the surface of pebbles by overwintering
females during the spring and early summer. After about a week the
eggs turn gray and as development progresses the reddish eye spots can
be seen through the chorion. Hatching occurred in 25 to 33 days at
Davis, California, but took 47 to 52 days at Berkeley, where it was
cooler. The egg burst in a crescent-shaped tear at the micropylar end
during hatching. Subsequent development to adult took about 76 days
(04).
REPRODUCTIVE CHARACTERISTICS:
Currently unknown for A. amargosus. Copulation of the Old World
Ilyocoris cimicoides (Linnaeus) and Aphelocheirus aestivalis
(Fabricius) was studied by Larsen who showed that the male typically
is astride the back of the female with his genital segments strongly
twisted and extended to engage the female. The Nearctic species A.
occidentalis La Rivers copulates in a similar fashion (04).
PARENTAL CARE:
Unknown.
POPULATION BIOLOGY:
Life History - 1 (DRAFT) - Life History
Species NAUCORID, ASH MEADOWS
Species Id ESIS501012
Date 13 MAR 96
Naucorids are parasitized by endo- and ectoparasites. Poisson
(1957) lists as endoparasites the flagellate Leptomonas naucoridis
Poisson in Naucoris maculatus Fabricius, and the chalcid wasp
Prestwichia aquatica Lubbock in Aphelocheirus. Water mites
(hydrachnids) are common ectoparasites of naucorids.
SPECIES INTERRELATIONSHIPS:
Unknown.
OTHER LIFE HISTORY DESCRIPTORS:
A. amargosus is known only from a single spring and this
flightless species may have narrow ecological tolerances that prevent
its dispersal through the Amargosa system (04).
Most naucorids breathe through the cuticle as nymphs, and through
spiracles in contact with an airstore as adults. They replenish their
subalar air bubble by breaking the surface film with the tip of the
abdomen; this airstore is connected with an air bubble which appears
as a silvery sheen on the pubescent venter. According to Parsons, the
most probable connections between the two airstores is the first
abdominal spiracular chamber and the lateral edges of the second
abdominal segment. The exposed ventral bubble, with its large surface
acts as a "physical gill" which transfers carbon dioxide out and
oxygen in, thus using the dissolved oxygen in the water as a secondary
air source. In the Naucoridae, as in all Nepomorpha, the subalar
airstore has at least one nonrespiratory function. Three pairs of
scolopophorous organs, presumably equilibrium sensors, lie in the air
space under the forewings. The genera and species of Naucoridae are
often quite specific as to their preferred habitat. A. amargosus La
Rivers is restricted to fast water where they cling to the stones and
crawl about, while other species swim amongst the pebbles in slower
waters (04).
Life History - 2 (DRAFT) - Management Practices
Species NAUCORID, ASH MEADOWS
Species Id ESIS501012
Date 13 MAR 96
MANAGEMENT PRACTICES
RESULT MANAGEMENT PRACTICE
Beneficial Maintaining/Controlling Water Flow
Beneficial Controlling water levels
Beneficial Reforestation
Beneficial Controlling/Removing Nonnative Vegetation
Beneficial Restricting Poaching
Beneficial Controlling/Removing Invertebrates
Beneficial Controlling/Removing Exotic Vertebrates
Adverse Predation
Existing Predation
Adverse Soil compaction by heavy equipment in mine areas
Existing Soil compaction by heavy equipment in mine areas
Adverse Groundwater drawdown
Existing Groundwater drawdown
Adverse Irrigating
Existing Irrigating
Adverse Dredging
Existing Dredging
COMMENTS ON MANAGEMENT PRACTICES -
The Ash Meadows naucorid occurs only in the thermal outflows
of the Point of Rock Spring in Ash Meadows, Nevada. The original
habitat as described by La Rivers in 1953 (01) consisted of scattered
spring outflows which exited from a rocky hillside and collected in a
small pond 30 feet long by 15 feet wide, which was in turn drained by
two outlet streams. This habitat has been substantially destroyed by
the creation of several large, deep, cold ponds where the small pond
and outflow streams formerly existed; the only portion of the habitat
still remaining in a relatively natural state is a set of very small,
shallow channels draining the thermal springs at the point where they
exit from cavities in the hillside. An examination of the locality by
D.A. Polhemus in 1984 (05) found these channels to be heavily choked
with tumbleweeds and brush for much of their length, with the insects
occurring only in the short unshaded stretches of channel immediately
below the spring origins. Significant alteration and destruction of
this species' extremely restricted habitat thus seems to have confined
the species to these few very short outflow channels below a thermal
spring.
The alterations to the habitat described above occurred as a
result channelization of the spring's outflow for agricultural
purposes and because of large scale modifications by a corporation
in anticipation of real estate, agriculture, and recreation
development (02). Since the purchase of the site by the Nature
Conservancy and its subsequent incorporation into a National Wildlife
Refuge these threats have ceased.
Future threats to the survival of the Ash Meadows naucorid are
diminuation of water flows from Point of Rocks Spring due to depletion
of the local aquifer, and clogging of the remaining outflow channels
by brush and debris. A periodic program of habitat inspection and
Management Practices - 1 (DRAFT) - Management Practices
Species NAUCORID, ASH MEADOWS
Species Id ESIS501012
Date 13 MAR 96
brush removal, allowing sunlight to reach the flowing water of the
channels, would be highly beneficial to the continued survival of this
species.
Introduced fishes and crayfish occur in Ash Meadows and are
potential predators of the Ash Meadows naucorid (02).
UNAPPROVED PLAN:
U.S. Fish and Wildlife Service. Agency Review 1986. Recovery Plan
for the Endangered and Threatened Species of Ash Meadows, Nevada.
169 pp.
The primary objective of the "Recovery Plan for the Endangered
and Threatened Species of Ash Meadows, Nevada" is to reclassify the
endangered-threatened populations to non-listed status by restoring
and protecting habitat which can support viable, self-sustaining
populations. The size and extent of populations need to be determined
for most species, and the habitats of all species except the spring-
loving centaury occur within the Ash Meadows essential habitat.
Except for the Devil's Hole pupfish and Warm Springs pupfish,
reclassification may be considered when threats have been removed and
when habitats/populations have been restored for a period of ten
years and to specified levels (as determined through research);
recovery of the Devil's Hole and Warm Springs pupfish will be
considered when their recovery tasks have been accomplished. The
general criteria for reclassifying/delisting the Ash Meadows naucorid
is summarized as follows:
A) protect Ash Meadows aquifer to maintain current (January 1986)
spring discharge;
B) determine historic distribution and population size by
surveying existing and potential habitats, and reviewing the
literature;
C) rehabilitate habitat to support populations throughout native
range. The extent of this habitat and size of populations to
be determined by research;
D) eliminate exotic species;
E) enforce all State and Federal laws and regulations; and
F) implement a public information and education program.
Management Practices - 2 (DRAFT) - References
Species NAUCORID, ASH MEADOWS
Species Id ESIS501012
Date 13 MAR 96
References
References - 1 (DRAFT) - References
Species NAUCORID, ASH MEADOWS
Species Id ESIS501012
Date 13 MAR 96
***** REFERENCES FOR ALL NARRATIVES EXCEPT N-OCCURRENCE *****
01 La Rivers, I. 1953. New gelastocorid and naucorid records and
miscellaneous notes, with a description of the new species,
Ambrysus amargosus (Hemiptera:Naucoridae). Wasmann Journal of Bio.
11:83-96.
02 U.S. Fish and Wildlife Service. 1985. Endangered and threatened
wildlife and plants; determination of threatened status with
critical habitat for six plants and one insect in Ash Meadows,
Nevada and California; and endangered status with critical habitat
for one plant in Ash Meadows, Nevada and CA. Fed. Reg.
50:20777-20794.
03 Usinger, R.L. 1946. Notes and descriptions of Ambrysus Stal with
an account of the life history of Ambrysus mormon Montd. (Hemiptera
Naucoridae). Univ. Kansas Sci. Bull., 31: 185-210.
04 Menke, A.S. 1979. Semiaquatic and aquatic Hemiptera of California
(Heteroptera: Hemiptera). Bulletin of the CA insect survey. Vol.
21. ISBN 0-520-09592-8 Univ. of CA Press. 2223 Fulton St. Berkeley
CA 94720.
05 Polhemus, D.A. 1986. Pers. comm. Univ. of Colo. Mus. Englewood,
80110.
06 Usinger, R.L. 1941. Key to the subfamilies of Naucoridae with the
generic synopsis of the new subfamily Ambrysinae. Ann. Entomol.
Soc. Am. 34:5-16.
07 Popov, Y.A. 1970. Notes on the classification of the recent
Naucoridae. Bull. Acad. Pol. Sci., Biol. 18: 93-98.
08 Popov, Y.A. 1971. Historical development of the hemipterous
infraorder Nepomorph. Tr. Paleontol. Inst. Akad. Nauk SSSR
129:1-228. (In Russian)
09 Nieser, N. 1975. The water bugs of the Guyana Region. Stud.
Fauna Suriname other Guyanas no. 59, 310 pp.
10 Parsons, M.C. and R.J. Hewson. 1976. Fine structure of the
triturating devices in the food pumps of Aphelocheirus and typical
Naucoridae. J. Morphol. 149:1-31.
11 IUCN Conservation Monitoring Centre. 1986. 1986 IUCN red list
threatened animals. Intern. Union for the Conserv. of Nature and
Nat. Res., ISBN No. 2-88032-605-2. 105 pp.
12 Uhler, P.R. 1884. Order IV. Hemiptera, pp. 204-296 In:
J. Kingsley, the Standard Natural History, Vol. 2, Boston, Cassino
8 Co., vii + 555 pp.
***** REFERENCES FOR N-OCCURRENCE NARRATIVE ONLY *****
01 La Rivers, I. 1953. New gelastocorid and naucorid records and
miscellaneous notes, with a description of the new species,
Ambrysus amargosus (Hemiptera: Naucoridae). Wasmann Journal of
Biology, 11:83-96.
02 Menke, A.S. 1979. Semiaquatic and aquatic Hemiptera of California
(heteroptera: Hemiptera). Bull. of the CA Insect Survey. Vol.
21. ISBN 0-520-09592-8 Univ. of CA Press. Berkeley. 94720.
References - 2