Systematics and acoustics of North American Anaxipha (Gryllidae: Trigonidiinae)
Thomas J. Walker [TW]
Department of Entomology and Nematology, University of Florida,
Gainesville,FL 32611, USA
Email: tjw@ufl.edu
David H. Funk [DF]
Stroud Water Research Center, Avondale, Pennsylvania, 19311, USA
Email: dfunk@stroudcenter.org
Key words: new species, type species, keys, male genitalia, DNA barcoding, calling songs, temperature
effects, sound production mechanics, carrier frequency determination, forewing movement cycles,
evolution of pulse rate
Note: For nomenclatural purposes the publication date of this ms will be the date that JOR makes the
work publicly available.
Abstract
The genus Anaxipha has at least 13 North American species, eight of which are described here.
Ten species fall into these three species groups: exigua group (exigua Say plus scia Hebard and
n. spp. thomasi, tinnulacita, tinnulenta, and tinnula); delicatula group (delicatula Scudder and
vernalis n. sp.); litarena group (litarena Fulton and rosamacula n.sp.). The remaining three
(imitator Saussure, fultoni n.sp., and calusa n.sp) have no close relatives among the other
species. Most new species were initially distinguished by their calling songs, and in most cases
sympatric populations proved cleanly separable by features of male genitalia and tooth-counts
of stridulatory files. Species groups were based mostly on comparisons of male genital
structures and the results of DNA barcoding. Species are here characterized not only by their
songs and morphology, but also by geographical, ecological, and seasonal distributions.
At a given temperature the pulse rate (PR) of the male’s calling song is a key aid to identification. PR at
25°C has a narrow range of variation within a species and among the 13 species its mean value varies
from 5 to 79 p/s. As in other crickets, pulse rates plotted as a function of temperature have a positive,
linear trendline. When trendlines for 11 Anaxipha species are extrapolated downward, the temperature
at ŷ=0 p/s is 2.7±2.2 (mean±SD)--i.e., the lines tend to converge at about 3°C. This makes possible a
simple formula for estimating the PR at 25°C from any Anaxipha calling song recorded at any
temperature. Other aids to identifying species from their calling songs are the duration and regularity of
breaks between pulse sequences and the relationship between PR and carrier frequency (CF). When CF
is plotted as a function of PR, the relationship deviates noticeably from linear only in vernalis.
We propose that in Anaxipha spp., as well as in six other genera in four gryllid subfamilies, the
synchrony of tooth impacts and the fundamental vibrations of the CF is maintained by the
scraper moving continuously over evenly spaced file teeth--rather than by the much-studied
(and well-established) catch-and-release mechanism of Gryllus spp. Our proposal is based on
the high rates of change in CF with temperature and on differences in the teeth of the
stridulatory files. The PR at 25°C of each of the 13 species is remarkable in the degree to which
it predicts the mean values of these five characters: file tooth number, tooth density, file
length, pulse duration, and pulse duty cycle (Fig. 17).
A neotype is designated for Gryllus pulicaria Burmeister (1838), the type species of the genus
Anaxipha. With the e-version of this paper, extensive Supporting Materials provide permanent
access to data sets that are the bases for our conclusions. These materials include detailed
records of the specimens examined and of the more than 1300 recorded songs that were
analyzed. Digitized versions of more than 450 of the recordings are archived in Cornell’s
Macaulay Library of Natural Sounds.
.
Systematics and acoustics of North American Anaxipha (Gryllidae: Trigonidiinae)
by Thomas J. Walker and David H. Funk
Title page……………………………………………………………………………………..2
Abstract……………………………………………………………….……………………….3
Introduction…………………………………………………………….……………………4
Methods………………………………………………………………….……………………7
Results…………………………………………………………………………………...…..13
Discussion…………………………………………………………………………………...29
Unresolved taxa…………………………………………………………………..29
Identification of species by calling songs………………………….….29
Identification of species based primarily on morphology…….33
Relationships among species……………………………………………….36
Mechanics of sound production in Anaxipha………..….……….…41
Acknowledgements………………………………………………..…………..…….…49
References……………………………………………………………………………….…..50
Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7
Fig. 8
Fig. 9
Fig. 10
Fig. 11
Fig. 12
Fig. 13
Fig. 14
Fig. 15
Fig. 16
Fig. 17
Fig. 18
Fig. 19
Geographic distribution of 12 spp.
Selected photos of Anaxipha parts
A. calusa photo gallery
PR and PRvs°C convergence as ID aids
3s calling song samples at ca25C
10s waveforms showing PT phrasing
CFvsPR trendlines for 13 spp
CFvsPR all records for 6 spp as ID aid
Typical examples of femoral stripes of 12 spp.
Box plots of ovipositor characters
Box plots of file-tooth counts for 13 spp.
Components of male genitalia
Examples of male genitalia of 12 spp.
Maximum likelihood tree
Waveforms of delicatula and tinnulenta
SEMs of file teeth
File & song characters plotted vs pulse rate
Log PP, PD, & PI vs log PR in 13 spp
Sexual differences in hind femur and body length
Table 1
Table 2
Table 3
Table 4
Table 5
Table 6
Worldwide no. & distribution of Anaxipha spp.
PR and convergence in Anaxipha calling songs
Barcode distance summary
Temperature coefficients for PRs and CFs
CFs in Anaxipha calling songs
Pulse durations and pulse duty cycles for Fig. 17