Journal of Animal Ecology
It is dominant to insularia melanics the genes for which occur at the same locus. The non-melanic, typical form is recessive. (2) On Merseyside insularia is rare and there is a marked cline in the frequency of carbonaria. In Liverpool and North Wirral the population is 85-97% carbonaria. The proportion falls so that in rural areas of Wales 50 km to the south-west it makes up less than 10% of the population. This situation provides a unique opportunity to study the dynamics of a cline. This can be done only by studying the situation in ecological terms. (3) A mark-release-recapture experiment estimated parameters of the population of male moths in a circular area (5 km radius) of Wirral during June 1968. Captures were made by assembling males to pheromone-producing females. Jolly’s model gave estimates of nightly population size ranging from 119 to 594. Fisher and Ford’s model (using Sheppard’s modification to allow for removal of marked animals and emigration) gave estimates of 233-489. Daily survival rates estimated by both models were between 0.3 and 0.4. About 30 584 moths (assuming 1: 1 sex ratio) emerged from pupal cases during the flying season of the species in 1968. This is equivalent to 390/km2. (4) Marked moths, released in a wood at the centre of the area flew up to 5.8 km a night. The relationship between the numbers of recaptures and the distance flown was complex. This and the fact that males were flying beyond the boundaries of the area in a night made it impossible to estimate the average distance of their flight. A significant proportion (20%) of recaptures were made 2 km or more from the point of release. An apparent tendency for males to fly south and west was examined. Data, because of the great variability in performance of assembling traps, were not adequate to dismiss or confirm this suggestion. (5) Female Biston betularia seldom fly and are not exposed to non-selective mortality such as that due to predation by bats. The 24-h `survival’ rates of carbonaria and typical females were estimated at seven places along the cline. This was done by glueing dead, previously frozen moths in life-like positions on tree trunks for 24 h where they were subject to predation by birds. Each day for many days a different randomly-selected series of eight trees was chosen from 100 and four of each morph were exposed. Birds were neither attracted to nor repelled from the moths by this procedure. The survival rates for carbonaria females decline with distance from Liverpool while those for the typical form increase. A direct comparison of the survival rates of males (via mark-release-recapture) and females is possible for only one locality. In Wirral carbonaria males have a rate of 0.3-0.4 while carbonaria females have one of about 0.75. (6) Mating and oviposition were observed in captive females. Males and females emerge from pupal cases in the evening and mate the same night. They remain in copula until late the next day. Most eggs are laid during the second and third days after emergence. Females may survive up to a week but produce few eggs during the latter half of their lives. (7) The survival rates of carbonaria and typical females at the seven localities along the cline and the pattern of oviposition were used to calculate selective coefficients of typicals to carbonaria. The regression of selective coefficient against distance from Sefton Park, Liverpool was significant (P
(1) Some populations of moths are polymorphic, containing industrial melanic and non-melanic forms. The melanics are camouflaged from bird predators in grimy, smoke polluted areas and non-melanics are conspicuous. The reverse situation occurs in unpolluted countryside. The carbonaria melanic of the peppered moth Biston betularia is almost totally black and is controlled by a single dominant gene.
For the love of moths | Beneficial animals and insects | Gardening Australia
Australia is a moth hotspot and that’s great for the environment and our gardens. Jane visits the Melbourne Museum to find out why.
Professor Ken Walker, senior curator of entomology at Museums Victoria, says that moths are the unsung heroes of Australian fauna. But the difference between butterflies and moths is a human division, he says: In nature, it doesn’t really work.
First theoretical difference is that butterflies fly during the day, but moths fly at night, but there are dayflying moths as well. Another difference is the antennae: In moths, they have very feathery antennae, whereas butterflies have just got a single antenna there. That’s because nightflying moths produce pheromones, so the males need large, feathery antenna to pick up female scent. Dayflying moths don’t rely on scent so much so have butterflyshaped antennae.
Moths vastly outnumber butterflies: There’s about 400 species of butterflies and 11,000 species of moths in Australia. It’s unlikely we’ll discover many new butterflies, but there are possibly another 10,000 or 20,000 moth species that we haven’t yet listed. This is partly because moths are excellent at diversifying they’re found in pretty much every part of Australia, even the arid centre.
Moths are critical species for our gardens – We often think of butterflies as good while moths are pests, but this isn’t the case; only a small handful of caterpillars give the rest a bad name, and most of these are introduced.
For gardeners, moths do an awful lot of pollination.
For bird lovers, 60% of our birds feed on insects, and a main part of their diet is moths. Many other animals also rely on them for food, so they’re an important part of our ecosystems. However habitat loss and climate change are affecting their life cycles.
Ken shows Jane some of the Museum’s moth collection, including:
Hercules moth (Coscinocera hercules), the biggest moth in the world, found in northern Australia
Cossid moths (family Cossidae), the adult form of witchetty grubs
Hawk moths (family Sphingidae), tremendous pollinators, with elegant markings
Emperor gum moth (Opodiphthera eucalypti), with two large ‘eye’ markings that makes it appear larger to predators
Bogong moth (Agrotis infusa), a small migratory moth that flies from Queensland to the Victorian Alps each summer.
Melbourne Museum’s moth collection is the second largest in Australia, and much of its curation is down to the work of volunteers such as moth experts, Peter Marriott and Marilyn Hewish.
They are gradually working through the thousands of moths, family by family, drawer by drawer, sorting the specimens and checking the correct names.
Jane visits Royal Park with volunteer Cathy Powers, who explains that moths need nectarproducing flowing plants to eat, as well as food plants for their larvae (caterpillars). “A diverse garden is really critical,” Cathy says. Local indigenous plants are best.
Bottlebrushes (Melaleuca spp., syn Callistemon spp.)
Melaleucas (Melaleuca spp.)
Blue hibiscus (Alyogyne hueglii)
Grevilleas (Grevillea cv.)
Cathy adds that mulch is also important, because some larvae eat the mulch and break it down for you, plus it protects the plants and soil underneath, and some moths lay their eggs in it.
As the sun sets, Peter, Cathy and Marilyn set up a white sheet with a spotlight to attract moths and see what is in the area.
One of the first moths is one that moth expert Marilyn has never seen before.
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