Chiggers of
the talmiensis group (Trombiculidae: Neotrombicula) in Russia and
neighbouring territories: taxonomic analysis using computer methods
A.A.
Stekolnikov
Parazitologiya, 30(5):
377-397 (1996) (In Russian, English summary).
S U M M A R Y
The study of morphological
variability in
three similar chigger species is carried out. The variability in
Neotrombicula talmiensis has been
for the first time studied in geographical aspect on the main part of
its range. Our collection in Western Caucasus supplied us with abundant
material on
N. carpathica and N.
pilosa. It is the first finding of these two species in
Russia and Caucasus. For all three species new localities and new hosts
are recorded. Complex characters has been produced for the purpose of
exact identification in the
talmiensis group, by the linear
discriminant analysis:
X1=93.25
– 0.42*AW – 0.41*AM – 0.87*Dm –
0.29*NDV + 0.38*PL,
X2=39.88
– 0.8*Dm – 0.6*NDV + 0.7*TaIII
Function X1
serve for separation of N. carpathica from
N. talmiensis. If X1>0, the
specimen measured belong to
N. talmiensis, if X1<0 — to
N.
carpathica. X2
let to separate N. pilosa from
N. carpathica. If X2>0, the
specimen should be attributed to
N. carpathica, if X2<0 — to
N.
pilosa.
The best sets of diagnostic
characters,
selected by discriminant analysis (AW, AM, Dm, NDV and PL for
N. talmiensis and N.
carpathica; Dm, NDV and TaIII for N. carpathica
and
N. pilosa), has been used to
obtain the picture of relative distances between samples by monotonic
multidimensional scaling.
Morphological differences, ecology
and joint
occurrence of the species are analysed. Some segregation of
N. carpathica and N.
talmiensis in the localities where the 2 species were found
together, dissociated areal of
N. carpathica (East Carpathians,
Caucasus and Tuva) and stable morphological difference between the 2
forms induced us to raise
N. carpathica to the specific
rank. In the line N. talmiensis—N. carpathica—N. pilosa
the requirements of humidity and temperature conditions appear to
increase. Probably, the increase of setae number and length along the
line may acquire ecological interpretation. This supposition is
confirmed indirectly by the diminutive character of
N. talmiensis from Kazakhstan and
Crimea. The question, whether the species are only ecological forms,
require more investigation.
Data bases, containing
morphometric,
collectional, bibliographical and taxonomic information on chiggers,
created by means of DBMS FoxPro, information system ZOOINT and original
computer programs were used in this study.
|
