Geographic Range
Although once widespread throughout southwest Australia, today
Parantechinus apicalis
is only found in small populations on the mainland. Two larger populations have
recently been found inhabiting Boullanger and Whitlock Islands in Jurien Bay in Western
Australia.
- Biogeographic Regions
- australian
Habitat
Southern dibblers on Whitlock Island prefer dense vegetation such as dunal scrubland
and succulent heath. This may be due to the protection it provides from predators
or an increased abundance of insect prey. Interestingly, when released from captivity
into the wild they take refuge in seabird burrows. On Boullanger Island there seemed
to be no preference of habitat as the entire island is fairly regular and has no trees.
- Habitat Regions
- temperate
- terrestrial
- Terrestrial Biomes
- desert or dune
Physical Description
Southern dibblers are small, with males averaging 145 mm in length and 60 to 100 g.
Male southern dibblers found on the mainland are generally heavier than island individuals.
Females are smaller at 140 mm average and 40 to 75 g. They have pointed snouts, long
whiskers, and strong jaws with sharp teeth. There are also grooves on the pads of
their feet which function in providing good traction. These, along with sharp claws,
allow them a good grip on trees and rocks.
Parantechinus apicalis
has rather coarse fur with a freckled appearance. The fur is brownish grey above
and grayish white with yellow underneath. They have hairy tapering tails and distinctive
white rings around large eyes.
- Other Physical Features
- endothermic
- homoiothermic
- bilateral symmetry
- polymorphic
- Sexual Dimorphism
- male larger
Reproduction
Typical behaviors prior to and during mating include sniffing of the cloacal and facial
regions and rump by both the male and female. This behavior is common and increases
in intensity as the female approaches estrous. Chases and attempted mountings are
frequent. The male may chase the female or vice versa. Often the animals vocalize
when they are chasing or attempting mountings. Mountings are initiated by the male
and there are many attempts that are unsuccessful. Chasing and unsuccessful mountings
may occur up to 15 days prior to copulation. Successful mountings involve the male
clasping the female in a neck-grip and a single copulation may continue for a few
hours.
- Mating System
- polygynandrous (promiscuous)
Paranechinus apicalis
will mate throughout March and April. Although females are only able to breed once
annually, males may be able to breed in multiple seasons. The gestation period for
southern dibblers is long compared to other small dasyurids, 44 to 53 days. Once
females give birth they carry up to eight young in a shallow pouch. The young are
dependent on the female for 3 to 4 months and usually disperse in September and October,
reaching sexual maturity in 10 to 11 months.
- Key Reproductive Features
- semelparous
- iteroparous
- seasonal breeding
- gonochoric/gonochoristic/dioecious (sexes separate)
- sexual
- viviparous
The extent of parental investment in southern dibblers involves the female carrying
and protecting her young in a shallow pouch. She provides food and protection until
the young reach independence and disperse in 3 to 4 months.
- Parental Investment
- altricial
-
pre-fertilization
- provisioning
-
protecting
- female
-
pre-hatching/birth
-
provisioning
- female
-
protecting
- female
-
provisioning
-
pre-weaning/fledging
-
provisioning
- female
-
protecting
- female
-
provisioning
Lifespan/Longevity
In captivity and in the wild
Parantechinus apicalis
individuals live 2 to 3 years. Interestingly, on Boullanger Island males display
semelparity where they die immediately after the breeding season. Extremely high
energy demands during the breeding season, elevated levels of free corticosteroids
in the blood, and related disease such as ulcers, anemia, and parasite infestation
ultimately cause the death of males. Because mainland males survive for multiple breeding
seasons, this male die-off could be environmentally determined. One possible explanation
is the effect of nesting seabirds including
bridled terns
and
white-faced storm petrels
on resources. Seabirds affect nutrients in the soil; post-breeding survival is significantly
higher on Whitlock Island which has many seabirds, 18 times more nutrients in the
soil and a larger amount of insects.
Behavior
Southern dibblers are active at both dawn and dusk hunting for large insects. If necessary,
they can jump or climb trees in order to catch their prey. During the day they take
shelter and rest in logs or between rocks. In reintroduced populations they form groups
which vary around 100 individuals.
- Key Behaviors
- terricolous
- crepuscular
- motile
- sedentary
- social
Home Range
No information on home range sizes in southern dibblers is was found.
Communication and Perception
Southern dibblers do vocalize, but vocalization is usually only heard during mating
and plays no role in the attraction of mates. There is no other information on how
P. apicalis
communicates, perceives its environment, or attracts mates, but related species rely
heavily on sight and smell.
Food Habits
Parantechinus apicalis
is primarily insectivorous, eating whatever insects they can find. Being a generalist
in this way may be advantageous due to fluctuating environmental conditions. Specifically
P. apicalis
has been found to eat grasshoppers (
Orthoptera
), cockroaches (
Blattaria
), beetles (
Coleoptera
), termites (
Isoptera
), and ants (
Hymenoptera
). Plant material, such as the berries of
Rhagodia baccata
, make up around 20% of its diet. Members of this species show no significant differences
in their diet during different seasons.
- Primary Diet
- carnivore
- Animal Foods
- insects
- Plant Foods
- fruit
- nectar
Predation
The color of the fur of southern dibblers is their best camouflage. They are also
able to move easily and with speed through dense vegetation and, for these reasons,
have few natural predators. Mainland populations are heavily preyed upon by introduced
red foxes
and
feral cats
.
- Anti-predator Adaptations
- cryptic
Ecosystem Roles
On the mainland southern dibblers prey on insects and are often prey to larger mammals.
On the islands southern dibblers face little danger of predation but compete with
introduced
house mice
for food.
Economic Importance for Humans: Positive
There are no known positive affects of Parantechinus apicalis on humans. They are a member of a unique fauna and may be of ecotourist interest because of their rarity.
- Positive Impacts
- ecotourism
Economic Importance for Humans: Negative
There are no known adverse affects of Parantechinus apicalis on humans.
Conservation Status
In 1902 southern dibblers were thought to be extinct but were rediscovered in 1967.
They have been threatened by human development, habitat destruction and burning, and
the introduction of foxes and cats. Southern dibblers are presently undergoing extensive
conservation efforts including successful translocations of captive-bred individuals
to Escape Island. Although this project is fairly new, initial success is high with
three generations surviving after the initial relocation.
Additional Links
Contributors
Tanya Dewey (editor), Animal Diversity Web.
Megan Coughlin (author), University of Michigan-Ann Arbor, Phil Myers (editor, instructor), Museum of Zoology, University of Michigan-Ann Arbor.
- Australian
-
Living in Australia, New Zealand, Tasmania, New Guinea and associated islands.
- native range
-
the area in which the animal is naturally found, the region in which it is endemic.
- temperate
-
that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).
- terrestrial
-
Living on the ground.
- desert or dunes
-
in deserts low (less than 30 cm per year) and unpredictable rainfall results in landscapes dominated by plants and animals adapted to aridity. Vegetation is typically sparse, though spectacular blooms may occur following rain. Deserts can be cold or warm and daily temperates typically fluctuate. In dune areas vegetation is also sparse and conditions are dry. This is because sand does not hold water well so little is available to plants. In dunes near seas and oceans this is compounded by the influence of salt in the air and soil. Salt limits the ability of plants to take up water through their roots.
- endothermic
-
animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.
- bilateral symmetry
-
having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.
- polymorphic
-
"many forms." A species is polymorphic if its individuals can be divided into two or more easily recognized groups, based on structure, color, or other similar characteristics. The term only applies when the distinct groups can be found in the same area; graded or clinal variation throughout the range of a species (e.g. a north-to-south decrease in size) is not polymorphism. Polymorphic characteristics may be inherited because the differences have a genetic basis, or they may be the result of environmental influences. We do not consider sexual differences (i.e. sexual dimorphism), seasonal changes (e.g. change in fur color), or age-related changes to be polymorphic. Polymorphism in a local population can be an adaptation to prevent density-dependent predation, where predators preferentially prey on the most common morph.
- polygynandrous
-
the kind of polygamy in which a female pairs with several males, each of which also pairs with several different females.
- semelparous
-
offspring are all produced in a single group (litter, clutch, etc.), after which the parent usually dies. Semelparous organisms often only live through a single season/year (or other periodic change in conditions) but may live for many seasons. In both cases reproduction occurs as a single investment of energy in offspring, with no future chance for investment in reproduction.
- iteroparous
-
offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).
- seasonal breeding
-
breeding is confined to a particular season
- sexual
-
reproduction that includes combining the genetic contribution of two individuals, a male and a female
- viviparous
-
reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.
- altricial
-
young are born in a relatively underdeveloped state; they are unable to feed or care for themselves or locomote independently for a period of time after birth/hatching. In birds, naked and helpless after hatching.
- crepuscular
-
active at dawn and dusk
- motile
-
having the capacity to move from one place to another.
- sedentary
-
remains in the same area
- social
-
associates with others of its species; forms social groups.
- visual
-
uses sight to communicate
- acoustic
-
uses sound to communicate
- chemical
-
uses smells or other chemicals to communicate
- visual
-
uses sight to communicate
- tactile
-
uses touch to communicate
- acoustic
-
uses sound to communicate
- chemical
-
uses smells or other chemicals to communicate
- cryptic
-
having markings, coloration, shapes, or other features that cause an animal to be camouflaged in its natural environment; being difficult to see or otherwise detect.
- ecotourism
-
humans benefit economically by promoting tourism that focuses on the appreciation of natural areas or animals. Ecotourism implies that there are existing programs that profit from the appreciation of natural areas or animals.
- carnivore
-
an animal that mainly eats meat
- insectivore
-
An animal that eats mainly insects or spiders.
References
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