Morphology of the brown tree snake, Boiga irregularis, with a comparison of native and extralimital populations

2000 ◽  
Vol 48 (4) ◽  
pp. 357 ◽  
Author(s):  
Joan Whittier ◽  
Conrad Macrokanis ◽  
Robert T. Mason
Keyword(s):  
Solomon Islands ◽  
Natural Populations ◽  
Single Species ◽  
Morphological Characters ◽  
Nonparametric Analysis ◽  
Native Range ◽  
Boiga Irregularis ◽  
Brown Tree Snake ◽  
The Mean ◽  
Brown Tree Snakes

We conducted an analysis of the morphology of specimens of the brown tree snake, Boiga irregularis, from the native range of eastern and northern Australia, Papua New Guinea and the Solomon Islands. First, a cluster analysis was conducted to determine natural groupings in the data; however, no groupings based on morphological characters were found. Then the importance of additional factors such as geographical groupings and coloration was analysed in a nonparametric analysis of variance. Significant differences were found in the mean rankings of key characters such as dorsal mid-body, ventral and subcaudal scale counts. However, the amount of variation and the degree of overlap among populations and groupings precluded separating animals on the basis of these features. Our data support the recognition of a single species with two subspecies based on colour variation. We also compared the morphology of a sample of brown tree snakes from an extralimital population on Guam to that of this species in the areas of the native range. Our data supported suggestions of alliances of the Guam population with northern Papuan populations. However, the Guam population of the brown tree snake was found to be less variable than were localised natural populations. Morphologically, the Guam population is distinctive, suggesting that it has undergone significant morphological change since its introduction.

scholarly journals Trapping strategies for deterring the spread of Brown Tree Snakes from Guam

1998 ◽  
Vol 4 (4) ◽  
pp. 348 ◽  
Author(s):  
Richard M. Engeman ◽  
Michael A. Linnell
Keyword(s):  
Pacific Islands ◽  
Health Hazard ◽  
Economic Problem ◽  
Planning Tool ◽  
Boiga Irregularis ◽  
Terrestrial Vertebrates ◽  
Brown Tree Snake ◽  
Brown Tree Snakes ◽  
Trap Placement ◽  
Accidental Introduction

The accidental introduction of the Brown Tree Snake Boiga irregularis to Guam has resulted in the extirpation of most of the island's native terrestrial vertebrates, has presented a health hazard to infants and children, and also has produced an economic problem. Prevention of its dispersal through Guam's cargo traffic to other Pacific islands has become a high environmental priority. Trapping around ports and other cargo staging areas is central to an integrated pest management programme designed to deter dispersal of the species. In this study, perimeter trapping of forested plots characteristic of those found in port areas was found to be the most effective trap placement strategy, although trap lines cut through the plot interior or placed along a single plot boundary were also effective. Snake removal potentially can be modelled using an exponential decay over time, providing the manager with a planning tool. Population recovery of Brown Tree Snakes in trapped plots was found to be slow in the fragmented forested habitats found around ports.

Effectiveness of the detector dogs used for deterring the dispersal of Brown Tree Snakes

1998 ◽  
Vol 4 (3) ◽  
pp. 256 ◽  
Author(s):  
Richard M. Engeman ◽  
Daniel S. Vice ◽  
Danny V. Rodriguez ◽  
Kenneth S. Gruver ◽  
William S. Santos ◽  
...  
Keyword(s):  
Health Hazard ◽  
Infants And Children ◽  
Search Pattern ◽  
Economic Losses ◽  
Boiga Irregularis ◽  
Routine Procedure ◽  
Terrestrial Vertebrates ◽  
Brown Tree Snake ◽  
Brown Tree Snakes ◽  
Accidental Introduction

The accidental introduction of the Brown Tree Snake Boiga irregularis to Guam has resulted in the extirpation of most of the island's native terrestrial vertebrates, has created a health hazard to infants and children, and has resulted in economic losses. Cargo inspections using teams of handlers and their detector dogs form a last line of defense for preventing Brown Tree Snake dispersal from Guam. To assess the efficacy of the teams of handlers and their dogs for locating stowed Brown Tree Snakes, we planted Brown Tree Snakes (in escape-proof containers) in cargo without the knowledge of the handlers inspecting the cargo. We found that when an observer attended the inspection to monitor procedures, 80% of the planted snakes were located. Without an attending observer present, 70% of the planted snakes were discovered, but only after such plantings had become a routine procedure. Prior to the routine planting of snakes, efficacy was nearly 50% less (38%). The reasons some planted snakes were missed by the dog teams were split between: an insufficient search pattern by the handler, or the dog giving no discernable indication that a snake was present.

Stimulus control of predatory attack in the brown tree snake (Boiga irregularis)

1988 ◽  
Vol 9 (1) ◽  
pp. 77-88 ◽  
Author(s):  
Hobart M. Smith ◽  
Karl Kandler ◽  
Robert Lee ◽  
David Chiszar
Keyword(s):  
Stimulus Control ◽  
Chemical Cues ◽  
Boiga Irregularis ◽  
Choice Behaviour ◽  
Volatile Chemicals ◽  
Brown Tree Snake ◽  
Predatory Attack ◽  
Brown Tree Snakes

AbstractThree experiments studied predation upon neonatal rodents by brown tree snakes (Boiga irregularis). Experiment 1 showed that chemical cues arising from prey were used in foraging tests that could not be completed on the basis of vision alone. Experiment 2 provided only airborne chemical cues, and snakes performed at chance levels in selecting among odoriferous (baited) and non-odoriferous (unbaited) nests. Snakes performed above chance, however, when a chemical trail led to the baited nest (Experiment 3), suggesting that non-volatile chemicals are most important in guiding choice behaviour.

Systematics of Indo-Pacific fireflies with a redefinition of Australasian Atyphella Olliff, Madagascan Photuroluciola Pic, and description of seven new genera from the Luciolinae (Coleoptera: Lampyridae)

Zootaxa ◽  
2009 ◽  
Vol 1997 (1) ◽  
pp. 1-188 ◽  
Author(s):  
LESLEY A. BALLANTYNE ◽  
CHRISTINE LAMBKIN
Keyword(s):  
New Species ◽  
New Caledonia ◽  
Solomon Islands ◽  
Phylogenetic Analyses ◽  
Single Species ◽  
Morphological Characters ◽  
New Genera ◽  
Generic Status ◽  
The Republic ◽  
Republic Of Palau

This major systematic revision of fireflies (Coleoptera: Lampyridae) concentrates on the genera related to Atyphella Olliff in the Luciolinae. Seven new genera and 19 new species are described, which with two exceptions occur in the area encompassed by Australia, the Republic of Palau, Federated States of Micronesia, Papua New Guinea, Indonesia (West Irian), Solomon Islands, New Caledonia, Vanuatu and Fiji. Keys to the genera and subgenera of the Luciolinae are included. The revision is based upon a phylogenetic analysis of 343 morphological characters of males, females and larvae of 112 Luciolinae species, including the type species of the six genera and four subgenera of the Luciolinae sensu McDermott (1966). The genus Atyphella Olliff is redefined and redescribed from 23 species including 14 endemic Australian species, and nine species from the wider study area. A. leucura Olivier, A. scabra Olivier and A. testaceolineata Pic are redescribed. A. palauensis Wittmer is elevated to species level from A. carolinae palauensis Wittmer and redescribed. Aquilonia gen. n. is described for Aq. costata (Lea), transferred from Atyphella Olliff. Convexa gen. n. is described for C. wolfi (Olivier), transferred from Atyphella. Gilvainsula gen. n. includes the new species, G. similismessoria sp. n., and G. messoria (Olivier), transferred from Atyphella Olliff. Lloydiella gen. n. includes four species; Ll. majuscula (Lea) transferred from Atyphella, and three new species, Ll. japenensis sp. n., Ll. uberia sp. n., and Ll. wareo sp. n. Pygatyphella (Ballantyne) is elevated to generic status from Luciola (Pygatyphella) Ballantyne and redescribed from 22 species including ten new species Pygat. japenensis sp. n., Pygat. karimui sp. n., Pygat. kiunga sp. n., Pygat. limbatifusca sp. n., Pygat. nabiria sp. n., Pygat. okapa sp. n., Pygat. russellia sp. n., Pygat. tomba sp. n., Pygat. uberia sp. n., and Pygat. wisselmerenia sp. n., with uberia representing specimens known in previous analyses as ‘Sisiak’. Pygat. eliptaminensis (Ballantyne), Pygat. marginata (Ballantyne), Pygat. peculiaris (Olivier) and Pygat. pulcherrima (Ballantyne) are transferred from Luciola (Pygatyphella) Ballantyne. Pygat. tagensis (Ballantyne), Pygat. hounensis (Ballantyne), Pygat. obsoleta (Olivier), and Pygat. undulata (Pic) are transferred from Atyphella Olliff; Pygat. obsoleta is reassessed, geographic varieties are suggested, and the species redescribed from a greatly expanded number of specimens. Pygat. ignota (Olivier), Pygat. plagiata (Blanchard) and Pygat. salomonis (Olivier) are transferred from Luciola Laporte and redescribed. Pygat. limbatipennis (Pic) is transferred from Atyphella salomonis var limbatipennis Pic, and redescribed. Magnalata gen. n. is described for three species, M. rennellia sp. n., M. limbata (Blanchard) transferred from Luciola, and M. carolinae (Olivier) transferred from Atyphella. Missimia gen. n. is erected for a single species M. flavida sp. n. based on four specimens dealt with in previous phylogenetic analyses as ‘Mt Missim’. Photuroluciola Pic is elevated to generic status from Luciola (Photuroluciola) Pic and redescribed from its single species Photuro. deplanata Pic. Asymmetricata gen. n. is erected for two SE Asian species As. ovalis (Hope) and As. circumdata (Motsch.), both transferred from Luciola and redescribed. Where available, females are associated and are characterised briefly. A. testaceolineata, M. limbata, Pygat. huonensis, Pygat. limbatipennis, Pygat. peculiaris, and Pygat. uberia sp. n. are identified by light patterns. Discussion addresses: the interpretation of female aptery, the extent of the labrum, numbering of abdominal segments using actual segment number, and use of the term ventrite to reflect visible abdominal sternites. Functional morphology of many terminal abdomen modifications is addressed as is the range and nature of colour patterns. Determination of polarity in various states of bipartite light organs is overviewed, as are problems with the homology of characters, and difficulties in interpretation of characters in soft bodied insects especially those preserved in ethanol.

Seasonal Testicular Development and Sperm Storage in Tropical and Subtropical Populations of the Brown Tree Snake (Boiga irregularis)

1997 ◽  
Vol 45 (5) ◽  
pp. 479 ◽  
Author(s):  
Karina H. Bull ◽  
Robert T. Mason ◽  
Joan Whittier
Keyword(s):  
Seasonal Pattern ◽  
Sperm Storage ◽  
Early Summer ◽  
Testicular Development ◽  
Boiga Irregularis ◽  
Ductus Deferens ◽  
South Eastern ◽  
Brown Tree Snake ◽  
Brown Tree Snakes ◽  
Reproductive Cycles

The seasonal pattern of testicular development of tropical and subtropical brown tree snakes, Boiga irregularis, was investigated. We also examined sperm storage in the reproductive tracts of both sexes. Males in south-eastern Queensland had a testicular cycle that was strongly seasonal, with testicular regression during the wet summer. Males from Papua New Guinea had a continuous testicular cycle, in which sperm was present in some animals every month. Females from south-eastern Queensland had no stored sperm or sperm storage receptacles in their oviducts. Sperm was found in only one of 28 female reproductive tracts. The sperm was located in the lumen, suggesting recent insemination. In contrast, the presence of sperm in the ductus deferens of most males in both populations indicated that males store sperm. This facilitates the apparent dissociation between the male and female reproductive cycles that has been reported previously in south-eastern Queensland populations. Male B. irregularis must store sperm for at least six months, from the time of maximal testicular development in autumn, until ovulation occurs in spring and early summer. This pattern of reproduction in B. irregularis fits neither a postnuptial nor a prenuptial pattern, as has been observed in a few other tropical snakes.

Implications of brown tree snake captures from fences

1999 ◽  
Vol 26 (1) ◽  
pp. 111 ◽  
Author(s):  
Richard M. Engeman ◽  
Michael A. Linnell ◽  
Phillip Aguon ◽  
Anthony Manibusan ◽  
Steven Sayama ◽  
...  
Keyword(s):  
Integrated Approach ◽  
Horizontal Position ◽  
Boiga Irregularis ◽  
Steel Cable ◽  
Management Implications ◽  
Brown Tree Snake ◽  
Chain Link ◽  
Sea Ports ◽  
The Difference ◽  
Brown Tree Snakes

The capture of brown tree snakes (Boiga irregularis) from fence lines in the vicinities of air and sea ports is an important component of the integrated approach used for curtailing the dispersal of the species from Guam. Use of fences by brown tree snakes was characterised from over 600 captures of snakes during spotlight searches. Two construction designs of chain-link fences were searched, the difference being whether a horizontal bar or a steel cable was used to support the chain link on top. Both fence designs had snakes concentrated at the fence tops – fences having top bars produced 92% of captures on the top third of the chain link, the top bar, or the parallel barbed-wire strands above the fence; fences without top bars produced 82% of captures from the top third of the chain link or the wires above it. Most snakes were found in a horizontal position and no general trends were found through the night for when snakes ascend or descend the fences. To help concentrate snakes at the tops of fences for facilitating control efforts, we recommend the use of a horizontal bar to support the chain link on top, as well as the use of parallel barbed- wire strands above the fence. We discuss management implications for using searches of fences to control brown tree snakes and to detect new brown tree snake populations in other locales.

scholarly journals Survival analysis of a stochastic delay single-species system in polluted environment with psychological effect and pulse toxicant input

2020 ◽  
Vol 2020 (1) ◽  
Author(s):  
Xiangjun Dai ◽  
Suli Wang ◽  
Weizhi Xiong ◽  
Ni Li
Keyword(s):  
Sufficient Conditions ◽  
Single Species ◽  
Threshold Value ◽  
Psychological Effect ◽  
Polluted Environment ◽  
Population System ◽  
Stochastic Delay ◽  
Species Population ◽  
The Mean ◽  
Single Species Population

Abstract We propose and study a stochastic delay single-species population system in polluted environment with psychological effect and pulse toxicant input. We establish sufficient conditions for the extinction, nonpersistence in the mean, weak persistence, and strong persistence of the single-species population and obtain the threshold value between extinction and weak persistence. Finally, we confirm the efficiency of the main results by numerical simulations.

scholarly journals GENETIC LOAD IN NATURAL POPULATIONS: IS IT COMPATIBLE WITH THE HYPOTHESIS THAT MANY POLYMORPHISMS ARE MAINTAINED BY NATURAL SELECTION?

Genetics ◽  
1974 ◽  
Vol 77 (3) ◽  
pp. 569-589
Author(s):  
Martin L Tracey ◽  
Francisco J Ayala
Keyword(s):  
Drosophila Melanogaster ◽  
Natural Selection ◽  
Natural Population ◽  
Natural Populations ◽  
Genetic Load ◽  
Structural Genes ◽  
Invertebrate Species ◽  
Average Proportion ◽  
Mean Fitness ◽  
The Mean

ABSTRACT Recent studies of genetically controlled enzyme variation lead to an estimation that at least 30 to 60% of the structural genes are polymorphic in natural populations of many vertebrate and invertebrate species. Some authors have argued that a substantial proportion of these polymorphisms cannot be maintained by natural selection because this would result in an unbearable genetic load. If many polymorphisms are maintained by heterotic natural selection, individuals with much greater than average proportion of homozygous loci should have very low fitness. We have measured in Drosophila melanogaster the fitness of flies homozygous for a complete chromosome relative to normal wild flies. A total of 37 chromosomes from a natural population have been tested using 92 experimental populations. The mean fitness of homozygous flies is 0.12 for second chromosomes, and 0.13 for third chromosomes. These estimates are compatible with the hypothesis that many (more than one thousand) loci are maintained by heterotic selection in natural populations of D. melanogaster.

Diet mixing in an aquatic carnivore, the harbour seal

2005 ◽  
Vol 83 (6) ◽  
pp. 851-859 ◽  
Author(s):  
Stephen J Trumble ◽  
Michael A Castellini
Keyword(s):  
Dry Matter ◽  
Single Species ◽  
Pacific Herring ◽  
Mixed Diet ◽  
Feeding Frequency ◽  
Digestible Energy ◽  
Diet Mixing ◽  
Walleye Pollock Theragra Chalcogramma ◽  
Harbour Seals ◽  
The Mean

To determine the effects of diet mixing on digestive performance, harbour seals (Phoca vitulina L., 1758) were offered either pure diets of Pacific herring (Clupea pallasii Valenciennes, 1847) or walleye pollock (Theragra chalcogramma (Pallas, 1814)) or a 1:1 mix of herring and pollock. Regardless of diet, retention time decreased approximately 40% as intake quadrupled. The mean apparent digestible dry matter (ADDM) was greatest on mixed diets during low feeding frequency trials; ADDM during high feeding frequency trials was significantly reduced as intake increased for animals on the single-species (pollock or herring) diets. As intake increased, up to 45% more digestible energy was assimilated from the mixed diet than from either single-species diet. The findings of this study suggest that a mixed diet consisting of prey differing in lipid and protein amounts increased digestible energy intake in harbour seals. Our measures of intake and ADDM in harbour seals revealed digestive flexibility and indicated that digestion in harbour seals was more efficient on a mixed diet.

scholarly journals Back-Calculation of Fish Size in Diet Analysis of Piscivorous Predators: A New Index for the Alien Silurus glanis

2021 ◽  
Vol 13 (8) ◽  
pp. 4322
Author(s):  
Renato Bacchetta ◽  
Andrea Marotta ◽  
Alessandro Nessi ◽  
Paolo Tremolada
Keyword(s):  
Diet Analysis ◽  
Native Range ◽  
Top Predator ◽  
Silurus Glanis ◽  
K Index ◽  
Caudal Vertebrae ◽  
Back Calculation ◽  
Control Capability ◽  
The Mean ◽  
Bone Remains

The wels catfish Silurus glanis has been constantly spreading in many European basins, outside its native range. Being a voracious predator, it is considered to have a severe impact on local fish communities. In the Ticino River (Northern Italy), bones of S. glanis were found in feces from the top predator Lutra lutra. To estimate the control capability of L. lutra for this species and to back-calculate S. glanis’ size from its bone remains, whole skeletons from 27 differently sized S. glanis specimens were analyzed. A double pharyngeal element and all caudal vertebrae emerged as significant items for species identification. The mean length of the pharyngeal element was directly related to fish mass, while for vertebrae, a K-index was proposed to identify the position of each vertebra along the spine and, from this, to calculate the original fish mass. This methodology allowed us to establish that the length of the preyed S. glanis was 85–435 mm, and the ages were between 0+ and 2+ years. The proposed methodology opens new perspectives for more detailed studies on the efficiency of predation by piscivorous species on allochthonous ones.

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