EFFECT OF TEMPORAL FACTORS ON REPRODUCTIVE ISOLATION BETWEEN CHORISTONEURA OCCIDENTALIS AND C. RETINIANA (LEPIDOPTERA: TORTRICIDAE)

1984 ◽  
Vol 116 (7) ◽  
pp. 991-1005 ◽  
Author(s):  
Andrew M. Liebhold ◽  
W. Jan A. Volney

AbstractThe seasonal distributions of Choristoneura occidentalis Freeman and C. retiniana (Walsingham) males attracted to pheromone sources overlapped considerably at two sites in south-central Oregon. Bimodality in the seasonal distributions of trapped males of both species was associated with a period of cool weather. The daily periods of female calling, and attraction of males to female-baited traps and to chemically baited traps overlapped greatly between the two species. However, these three aspects of C. occidentalis mating behavior began 1–2 h before those of C. retiniana. Under laboratory conditions, there was also considerable overlap in the calling periods of the two species; but again, C. occidentalis females initiated calling slightly earlier than did female C. retiniana. Females of both species continued to call many hours past the cessation of male attraction to pheromones in the field. Male attraction to pheromones occurred earlier on cool evenings than on warm evenings. Laboratory studies indicated a similar effect of temperature on timing of female calling. Little intraspecific variation in calling periodicity was observed among field-collected populations of each species. However, a C. occidentalis laboratory colony appeared to have partially lost its circadian rhythm of calling.

2000 ◽  
Vol 132 (6) ◽  
pp. 877-887 ◽  
Author(s):  
B.S. Lindgren ◽  
S.E.R. Hoover ◽  
A.M. MacIsaac ◽  
C.I. Keeling ◽  
K.N. Slessor

AbstractThe effects of lineatin enantiomer ratios, lineatin release rate, and trap length on catches and the flight periods of three sympatric species of Trypodendron Stephens were investigated in field bioassays using multiple-funnel traps. The ambrosia beetle, Trypodendron betulae Swaine, was caught in similar numbers in baited traps and blank control traps, showing that this species does not respond to lineatin. Our results confirmed that Trypodendron lineatum (Olivier) is attracted only to (+)-lineatin. Trypodendron rufitarsus (Kirby) and Trypodendron retusum (LeConte) were shown to utilize lineatin and like T. lineatum were caught only when (+)-lineatin was present. These results indicate that lineatin does not govern reproductive isolation among these three species. There was no effect by (+)-lineatin release rate within the range tested. The flight of T. rufitarsus commenced earlier and ceased before the peak of the T. lineatum flight, suggesting that temporal separation may be an important component of reproductive isolation between these two species. The flight period of T. retusum was similar to that of T. lineatum. Host odours may aid in reproductive isolation of these two species. Enantiomer blend did not significantly affect sex ratio in any species; however, sex ratio differed among species, indicating that different species responded differently to the traps or that natural sex ratios differ. Catches of T. rufitarsus and T. retusum increased with trap length when pheromone release per trap was held constant and when release was held constant relative to trap length. Trap length and release rate did not affect sex ratio.


2020 ◽  
Vol 20 (6) ◽  
Author(s):  
Fallon Fowler ◽  
Tashiana Wilcox ◽  
Stephanie Orr ◽  
Wes Watson

Abstract Understanding collection methodologies and their limitations are essential when targeting specific arthropods for use in habitat restoration, conservation, laboratory colony formation, or when holistically representing local populations using ecological surveys. For dung beetles, the most popular collection methodology is baited traps, followed by light traps and unbaited flight-intercept traps during diversity surveys. A less common collection method, flotation, is assumed to be laborious and messy, and so only a handful of papers exist on its refinement and strengths. Our purpose was threefold: First, we tested the recovery and survival rates of Labarrus (=Aphodius) pseudolividus (Balthasar) and Onthophagus taurus (Schreber) when floating beetle-seeded dung pats to determine potential collection and safety issues. We collected 72.4 and 78% of the seeded L. pseudolividus and O. taurus, respectively, with >95% survival rating. Second, we developed a flotation-sieving technique that enables users to rapidly collect and passively sort dung beetles with less time and effort. Specifically, we often collected 50–100 g of wild dung beetles within a couple of hours of gathering dung and sorted them in a couple more by allowing dung beetles to sort themselves by size within a series of sieves; Third, we reviewed flotation-based advantages and disadvantages in comparison to other methodologies.


1995 ◽  
Vol 52 (7) ◽  
pp. 1406-1420 ◽  
Author(s):  
R. A. Reid ◽  
K. M. Somers ◽  
S. M. David

Surveys of benthic invertebrates have revealed patterns attributed to the impacts of acid deposition. Unfortunately, these patterns may be confounded by temporal variation that will affect follow-up studies of the recovery of these communities. Here, we assess spatial and temporal variation in time-limited, kick-and-sweep collections of littoral-zone benthos. Spatial variation comprised five sites representing the predominant nearshore substrates in each of three lakes. Temporal variation spanned a different scale in each lake with five sites sampled: (i) twice on the same day, (ii) once a week for 3 weeks, and (iii) four times through the ice-free season. Variation was quantified using a model II analysis of variance. Spatial differences predominated in same-day samples (60.4% of the variation on average) and those collected over a 3-week period (46.1%). In contrast, samples collected over the ice-free season revealed that spatial and temporal factors accounted for 9.4 and 25.6% of the variation. We conclude that our collections of littoral macrobenthos are highly repeatable if sampling is restricted to short periods (e.g., 3 weeks). Surveys spanning longer periods may incorporate considerable temporal variation from seasonal changes in abundance.


1961 ◽  
Vol 93 (10) ◽  
pp. 855-859 ◽  
Author(s):  
K. R. Depner

Siphona irritans (L.), commonly known as the horn fly, is a serious pest of cattle. In southern Alberta, ten thousand flies have been counted on a single host animal. Properly conducted control studies require the establishment of a permanent laboratory colony. Previous attempts to establish such a colony had not been successful (McLintock and Depner, 1957) as more information about the biology of the fly was needed. The results presented in this paper will help provide this information.


1987 ◽  
Vol 119 (5) ◽  
pp. 465-480 ◽  
Author(s):  
Thomas W. Phillips ◽  
Stephen A. Teale ◽  
Gerald N. Lanier

AbstractPissodes approximatus Hopkins (1911) is a junior subjective synonym of P. nemorensis Germar (1824). The conspecificity of these entities, traditionally considered distinct based only on distribution and slight morphological differences, is corroborated here with comparative studies of ecology, behavior, and morphology. When pheromone-baited traps were deployed during the spring (May–June) and fall (November–December) in several localities to examine seasonal activity, southern populations (P. nemorensis sensu Hopkins) responded only in the fall and northern populations only in the spring, but a population in Virginia responded during both seasons. Laboratory studies found that individuals from five southern populations became reproductively mature under 16:8, 12:12, and 8:16 (L:D) photoperiods but weevils in a New York population did not mature under the 8:16 photoperiod. A two-species model based on strict seasonal isolation between northern and southern populations is rejected. Morphometrics revealed significant differences in six body dimensions and three morphometric ratios among 13 populations, but there was no geographic pattern of differences to suggest the existence of two species. Sexual dimorphism in rostrum length was most pronounced in southern populations but occurred in all five populations in which it was investigated. Examination of male and female genitalia revealed similar variation in northern and southern populations and conflicted with previously reported diagnostic differences. Our study and the results of earlier work lead us to conclude that the populations previously represented by the names P. nemorensis and P. approximatus comprise one widely distributed species and display intraspecific variation in life history and morphological characters.


1995 ◽  
Vol 127 (6) ◽  
pp. 813-830 ◽  
Author(s):  
R.F. Shepherd ◽  
T.G. Gray ◽  
G.T. Harvey

AbstractMale moths of Choristoneura occidentalis Freeman, C. biennis Freeman, C. fumiferana (Clemens), and C. orae Freeman were caught in pheromone-baited traps. Ten traps were placed at each site, five baited with an aldehyde lure and five with an acetate lure. This procedure permitted separation of species based on the specific chemical lure and also provided specimens for further study of morphological and isozyme differences. The color of the forewings, presence or absence of spicules on the aedeagus, and a specific allozyme frequency were determined on selected specimens where these characteristics were useful in separating species at a particular site. Distributions of all species were more extensive than previously known, sometimes adding hundreds of kilometres to the recorded range. Areas of sympatry were identified and the fidelity and usefulness of characteristics for separating species in areas of overlap were discussed.


1993 ◽  
Vol 71 (6) ◽  
pp. 1136-1145 ◽  
Author(s):  
Keith M. Somers ◽  
Roger H. Green

Crayfish were trapped in six south-central Ontario lakes to examine seasonal changes in estimates of relative abundance. Baited-trap catches of Cambarus bartoni and Orconectes virilis correlated with changes in water temperature. Cambarid catches increased in the spring until a midsummer maximum, but dropped suddenly as the water temperature began to fall in August. Ovigerous (i.e., egg-bearing) females and recently moulted males were captured by SCUBA divers in August. Trap catches increased, once breeding and moulting periods concluded, and subsequently decreased as water temperatures continued to drop in the autumn. In contrast, catches of male O. virilis increased in the spring and remained relatively constant throughout the summer until water temperatures fell in September. Catches of female O. virilis peaked somewhat later in the summer and then gradually declined in the early fall. Although the two species and the two sexes differed in the length of the midsummer sampling period when trap catches were relatively constant, similar seasonal trends among lakes suggest that midsummer trap catches can be used to estimate crayfish relative abundance. Other factors, such as the presence of smallmouth bass (Micropterus dolomieui), lake physical and chemical characteristics, and the number of co-occurring crayfish species also correlated with trap catches. Both the presence of bass and the number of co-occurring species of crayfish probably affect crayfish behaviour and activity, thereby reducing catches in baited traps, but not necessarily affecting actual population abundance. Comparisons of relative abundance based on catches from baited traps must control for these seasonal behavioural, and environmental factors.


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