Short notes on Hydrophilidae, I. -
Miguel Archangelsky
Beetles, surf, and sun or insect
collecting in the West Indies -
Keith Philips
Short Notes on Hydrophilidae, I.
Adult hydrophilids can be considered a fairly well known group
of beetles in the United States and Canada. But, as it happens with
many other families of insects, new species are being described on a
regular basis.
In this note I want to call your attention to some characters used
to separate two species included within the genus Berosus, B.
peregrinus and B. aculeatus. The genus Berosus
is one of the largest (in number of species) within the Hydrophilidae,
as it has over 200 species worldwide; 26 occur in North America, north
of Mexico. B. peregrinus is one of the most common species,
and is widely distributed throughout North America. B. Aculeatus
is present in the eastern United States, with Michigan and New York as its
northern limits.
Both species are very similar in size, shape and color. The only way
for the entomologist not familiar with them to tell them apart is by the
male genitalia. There are also a few external morphological characters
that help in their identification, but they do not seem to be constant
in all the specimens that I have seen. Some of these characters are used
in keys, and if you do not have reference specimens for comparison, they
can mislead in the identification. The following are a few comments on
two of those characters.
1. Elytral apices:
B. peregrinus: males have rounded elytral apices, while females
have slightly pointed elytral apices (Figs. 1 and 2).
B. aculeatus: males have slightly pointed apices (they
look very similar to female B. peregrinus); those of the
females are strongly pointed (Figs. 3 and 4).
Elytra with preapical tubercle on second interval:
B. peregrinus: in the literature both males and females are
mentioned as lacking those tubercles, but in the specimens I have seen,
they are present. These tubercles are small and not as well developed
as in B. aculeatus, but they are still present (Figs. 1 and 2).
This is one character that misled me in my early identifications.
B. aculeatus: both males and females have those tubercles, and
they are well developed (Figs. 3 and 4), but for comparison with specimens
of B. peregrinus, reference specimens may be required to figure
out which is "more strongly developed".
I hope that these hints will be helpful for all those die-hard
hydrophilidists that are out there.
- Miguel Archangelsky
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Beetles, Surf, and Sun
or
Insect Collecting
in the West Indies
With my recent trip to the West Indies over Christmas and my previous travels
to this area (not to mention my lack of submissions to this publication)
I thought it was about time that I wrote an article about some of my
experiences in a few of these islands. I have spent about a total of about
two months in this area on three territories; the Dominican Republic,
Jamaica, and the British Virgin Islands. This article will serve as an
introduction for a series of articles giving more specific information
on each of the areas that I have visited. The information will be in
travelogue format which hopefully will give any of you useful information
for planning and having a successful trip to these areas.
For readers less familiar with this area, the following background
information should prove useful. The West Indies are composed of two main
groups of islands, the Greater Antilles composed of Cuba, Jamaica, Hispaniola,
Puerto Rico, the Bahamas, and the smaller associated isands, and the
Lesser Antilles in the south made up of a series of small, relatively recent,
volcanic islands. The two groups are linked by the Virgin Islands which are
most similar faunistically to Puerto Rico, as they are linked in one land
mass (except for St. Croix) during lower sea levels, and are known as the
Puerto Rican Grand Bank. One should note that the islands of Trinidad,
Curacao, Bonaire, and Aruba are not part of the West Indies, with a different
origin and a fauna very closely associated with South America.
The West Indian fauna has many complex affinities, with beetle species in
common with and related to the Americas, as expected, but also to Africa
(for example, Anoplodrepanus, a neat little scarabaeine genus
on Jamaica), Asia (the scarabeine Canthonella and the anthribid
Cryptoxenus), and Australia (the tenebrionid genus archaeoglenes).
What these relationships indicate is first, the great age of the antillian
fauna and second, the probable confounding effects of extinction.
Insect species of the different islands can often be quite variable due to
founder effects and partial or total isolation for some of the populations.
One should use caution when describing species which initially appear distinct.
This induced variation is, I think, part of the inherent attractiveness
of this group of islands.
With this bit of background it may be pertinent to mention at this point
how many people regard the West Indies as relatively depauperate and if
given the choice would rather go to Mexico, Central America, or other
such places. In actual fact, the collecting can be slower and more
difficult than on mainland areas, but the ability to collect undescribed
species is just as good on these islands, particularly if one limits
his or her travels to the four large islands. For example, on a month long
trip to the Dominican Republic, many specialists were amazed at the number
of undescribed taxa my former advisor and I had collected. Even
in our relatively unspecialized general beetle collecting, we managed to
collect six undescribed species of scarabaeines, which are a relatively
well known group of beetles. Additionally, we collected the first record
in the West Indies of a Micropeplidae, an interesting beetle related to
or part of the Rove beetle family, Staphylinidae. Even on some
of the smaller islands fascinating insects can be observed and collected.
On my most recent trip to Tortola (British Virgin Islands) I collected
another specimen of an undescribed genus of ptinid (spider beetle)
endemic to the West Indies and possibly an undescribed species of
Canthochilum, another West Indian endemic dung beetle genus.
Cerambycids were moderately abundant and perhaps I collected at best, 15
species. This isn't a lot, but not too bad for the dry season.
For the most diverse habitats, stick to the large islands with the
highest elevations, which provide a gradient of habitat types. On Jamaica,
habitats range from mangrove, dune, and cactus-thorn-scrub down along
the coast, up through to dry limestone scrub forest, wet limestone forest,
montane forest, and finally elfin woodland. Particularly interesting
is the elfin woodland which is a cloud forest with trees only about
15-20 feet high with limbs heavily festooned with moss and lichens.
Practically every species collected at this altitude is endemic.
The highest island in the West Indies is Hispaniola which reaches an
altitude of about 10,000 feet. The forests at these higher elevations are not
cloud forests in the traditional sense but instead consist of caribbean
pine forests which grow in a relatively open spaced distribution. Epithetic
lichens coat the tree branches and give one the appearance of some
pine forests in the south-eastern U.S. that I have seen.
- Keith Philips
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