''Synanthedon myopaeformis'' is a
moth
Moths are a paraphyletic group of insects that includes all members of the order Lepidoptera that are not butterflies, with moths making up the vast majority of the order. There are thought to be approximately 160,000 species of moth, many of w ...
of the family
Sesiidae
The Sesiidae or clearwing moths are a diurnal moth family in the order Lepidoptera known for their Batesian mimicry in both appearance and behaviour of various Hymenoptera.
The family consists of 165 genera spread over two subfamilies, contai ...
and the order ''
Lepidoptera''. In Europe it is known as the red-belted clearwing and in North America as the apple clearwing moth. The
larva
A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle.
...
e create galleries under the bark of fruit trees, especially old trees with damaged trunks. During this process, the larvae cause significant damage to host trees. Particular attention has been paid to the damage they cause to apple trees. Their status as a pest of
apple
An apple is an edible fruit produced by an apple tree (''Malus domestica''). Apple trees are cultivated worldwide and are the most widely grown species in the genus ''Malus''. The tree originated in Central Asia, where its wild ancestor, ' ...
orchards has led to many research projects aimed at controlling populations of the moth. This moth is native to
Europe
Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a subcontinent of Eurasia and it is located entirel ...
, the
Near East and
North Africa
North Africa, or Northern Africa is a region encompassing the northern portion of the African continent. There is no singularly accepted scope for the region, and it is sometimes defined as stretching from the Atlantic shores of Mauritania in ...
. Recently, the moth was introduced into North America, being first detected in Canada in 2005. There are several organisms that threaten the larvae, including
parasitoids,
nematodes, and
bacteria
Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one Cell (biology), biological cell. They constitute a large domain (biology), domain of prokaryotic microorganisms. Typically a few micrometr ...
.
Subspecies
* ''Synanthedon myopaeformis cruentata''
(Mann, 1859)
* ''Synanthedon myopaeformis graeca''
(Staudinger, 1871)
* ''Synanthedon myopaeformis luctuosa''
(Lederer, 1853)
* ''Synanthedon myopaeformis myopaeformis''
* ''Synanthedon myopaeformis typhiaeformis''
(Borkhausen, 1789)
Geographic range
''Synanthedon myopaeformis'' is native to north
Africa
Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...
,
western Asia
Western Asia, West Asia, or Southwest Asia, is the westernmost subregion of the larger geographical region of Asia, as defined by some academics, UN bodies and other institutions. It is almost entirely a part of the Middle East, and includes Ana ...
, and
Europe
Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a subcontinent of Eurasia and it is located entirel ...
, where it is known as the red-belted clearwing moth. In 2005, it was discovered in southwestern
Canada
Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by tot ...
and has since been found in the
United States
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territori ...
. Throughout North America, ''S. myopaeformis'' is known as the apple clearwing moth because of its status as a pest of apple trees.
Morphology
![Synanthedon myopaeformis, Lodz(Poland)03(js)](https://upload.wikimedia.org/wikipedia/commons/7/73/Synanthedon_myopaeformis%2C_Lodz%28Poland%2903%28js%29.jpg)
Adults are blue-black in color with a dark orange-red stripe across their segmented abdomen. The moths have short, bushy tails. Their wings are clear in the middle with dark edges framed by short fringe. Wingspan varies between 1.8 and 2.8 cm at the forewings, with forewings narrower and longer than hindwings.
Caterpillars are 2.5 cm long, with off-white bodies and a reddish-brown head.
Pupa
A pupa ( la, pupa, "doll"; plural: ''pupae'') is the life stage of some insects undergoing transformation between immature and mature stages. Insects that go through a pupal stage are holometabolous: they go through four distinct stages in thei ...
e are around 1.5 cm long,
and are golden brown with two
tubercle
In anatomy, a tubercle (literally 'small tuber', Latin for 'lump') is any round nodule, small eminence, or warty outgrowth found on external or internal organs of a plant or an animal.
In plants
A tubercle is generally a wart-like projection ...
s, short projections, protruding from their heads. They can be seen sticking out of the bark of apple trees.
Habitat
Because the life cycle of the moth is dependent on host trees, ''S. myopaeformis'' is found predominately near apple orchards.
They are also found in gardens, woodlands and
hedge
A hedge or hedgerow is a line of closely spaced shrubs and sometimes trees, planted and trained to form a barrier or to mark the boundary of an area, such as between neighbouring properties. Hedges that are used to separate a road from adjoin ...
rows. The larvae feed under the bark of
apple
An apple is an edible fruit produced by an apple tree (''Malus domestica''). Apple trees are cultivated worldwide and are the most widely grown species in the genus ''Malus''. The tree originated in Central Asia, where its wild ancestor, ' ...
trees,
crab apple
''Malus'' ( or ) is a genus of about 30–55 species of small deciduous trees or shrubs in the family Rosaceae, including the domesticated orchard apple, crab apples, wild apples, and rainberries.
The genus is native to the temperate zone o ...
s,
pear
Pears are fruits produced and consumed around the world, growing on a tree and harvested in the Northern Hemisphere in late summer into October. The pear tree and shrub are a species of genus ''Pyrus'' , in the family Rosaceae, bearing the po ...
s,
quinces,
plums,
cherries,
apricots,
hawthorn
Hawthorn or Hawthorns may refer to:
Plants
* '' Crataegus'' (hawthorn), a large genus of shrubs and trees in the family Rosaceae
* ''Rhaphiolepis'' (hawthorn), a genus of about 15 species of evergreen shrubs and small trees in the family Rosace ...
and
mountain ash Mountain ash may refer to:
* ''Eucalyptus regnans'', the tallest of all flowering plants, native to Australia
* Mountain-ashes or rowans, varieties of trees and shrubs in the genus ''Sorbus''
See also
* Mountain Ash, Rhondda Cynon Taf
Mounta ...
, favoring old
cankerous trees.
[
In Canada, it has been found that both male and female moths are attracted to the flowers of showy milkweed (''Asclepias speciosa'') and that it is the phenylacetaldehyde produced by the flowers that attracts them. This substance can be used in monitoring populations of the moth or in mass-trapping them.
]
Life cycle
Egg
Each female can lay up to 250 eggs. Eggs are laid singly on the bark of host trees, typically in cracks or damaged areas of the trunk and branches.
Caterpillar
After hatching, larvae bore into the bark of the host trees, digging into the phloem
Phloem (, ) is the living tissue in vascular plants that transports the soluble organic compounds made during photosynthesis and known as ''photosynthates'', in particular the sugar sucrose, to the rest of the plant. This transport process is c ...
of the tree. As they bore through the tree, they leave trails of waste that are visible from the outside of the tree. Larvae mature on the host tree for two years. During warm weather, the caterpillars move along the bark of the tree feeding on young plant tissues, including the buds of apple trees. At the beginning of winter, the caterpillars once again bore into the tree to spend the cold season under the bark. They emerge in early spring to feed. Larvae repeat this feeding – wintering cycle once more before emerging and boring a final hole in the bark in which to pupate.
Pupa
After burrowing into the bark, larvae compose golden brown cocoons which stick out from the tree. Compared to the larval stage, the pupal stage is much shorter at two weeks.
Adults
Adults emerge from their cocoons in early summer.
Physiology
Flight activity
After emergence in early summer, adults are active in flight from May through August. Because ''Synanthedon myopaeformis'' thrives in warm weather, flight activity is temperature dependent. The adults are significantly less active on cold days compared to warm days. Flight activity ceases at the end of summer when average temperature drops to 15-16 °C.
Color vision
In 2014, Judd and Eby found that ''S. myopaeformis'' does not discriminate between yellow, green and white or between purple, blue, red, and black. The moths also display different behaviors toward traps reflecting green (500-550 nm) and ultraviolet (300-400 nm) light. A second study by Eby in 2012 showed that the moths are sensitive to the same wavelengths of light shown in the previously mentioned study, suggesting that the ''S. myopaeformis'' could have dichromatic vision.
Enemies
The parasitoid '' Liotryphan crassiseta'' is a significant cause of mortality in ''S. myopaeformis.'' Nematodes, '' Steinernema sp.,'' are a threat to larvae, and larva mortality following exposure to the fungi
A fungus ( : fungi or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as a kingdom, separately from ...
'' Beauveria bassiana'' and ''Metarhizium brunneum
''Metarhizium brunneum'', is the re-instated
name of a group of reassigned ''Metarhizium'' isolates, previously grouped in the species "''Metarhizium anisopliae'' var. ''anisopliae''": based on a multigene phylogenetic approach using near-comple ...
'' is common. Bacteria
Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one Cell (biology), biological cell. They constitute a large domain (biology), domain of prokaryotic microorganisms. Typically a few micrometr ...
are another threat to larvae. In 1999, Shehata, Nasr, and Tadros found that significantly fewer adults emerged from cocoons after larvae were exposed to the bacteria '' Bacillus thuringiensis.''
Mating
Pheremones
Males of the species respond to sex pheromone
A pheromone () is a secreted or excreted chemical factor that triggers a social response in members of the same species. Pheromones are chemicals capable of acting like hormones outside the body of the secreting individual, to affect the behavio ...
s released by the glands of females. A 2010 study from Judd, Gries, Aurelian, and Gries found that 3,13-octadecadienyl acetate is the primary sex hormone used by ''S. myopaeformis'' females. This chemical alone is enough to attract males, although the females do also produce secondary sex hormones in addition to 3,13-octadecadienyl acetate, these appear to play a minor role.
Interactions with humans
Pest status
Native to Europe, Asia, and northern Africa, but recently released in Canada and the United States, ''S. myopaeformis'' has been recognized as a significant threat to apple trees in these regions. Because the larvae bore holes and tunnels under and through the bark of their host trees, the presence of the species is harmful to the health and production of these trees. Previously, damage caused by ''S. myopaeformis'' was associated primarily with old, damaged, or otherwise sick apple trees because the lack of integrity of their bark allows the larvae easier access to the inner layers of the trunk and branches. However, their potential to harm even previously healthy apple trees is now recognized. Because of this, many methods have been tested for controlling the proliferation of the moth.
Attempted control methods
Pheromone disruption
One method of reproduction control involves the release of the ''S. myopaeformis'' sex pheromone into orchards infested by the species. The technique, mating disruption
Mating disruption (MD) is a pest management technique designed to control certain insect pests by introducing artificial stimuli that confuse the individuals and disrupt mate localization and/or courtship, thus preventing mating and blocking the ...
, leads to a dampened male response to female sex hormones, disrupting the mating process. As a result of the overabundance of pheromones, the percentage of mated females decreases relative to unmated females.
Pheromone traps
Many research studies have used pheromone trap
A pheromone trap is a type of insect trap that uses pheromones to lure insects. Sex pheromones and aggregating pheromones are the most common types used. A pheromone-impregnated lure, as the red rubber septa in the picture, is encased in a convent ...
s to monitor the population of ''S. myopaformis''. The traps enable monitoring of infestations even when the population is low, and so are an effective reference to determine the best time to apply pest-controlling measures or plant growth regulators.
Other chemical lures
Other methods of control focus on luring and trapping adults. A Hungarian study found that both male and female red-belted clearwings are attracted to a combination of pear ester and acetic acid. Because many pheromone-based traps attract more males than females, this method is suggested as female-targeted trapping.
Other species
Each of the species mentioned above in the “Enemies” section have been used to control populations. These include nematodes, fungi, and bacteria.
Trunk coatings
Diverse materials have been used to coat the bark of apple trees in an attempt to kill ''S. myopaeformis'' eggs and larvae. In 2010, the effectiveness of cotton seed oil, lime, and motor oil were tested in decreasing the number of adults and pupae. All three materials reduced the number of adult moths during the second year, but the oils showed the greatest effect.
References
External links
Red-belted Clearwing at UKmoths
Lepiforum.de
Vlindernet.nl
{{Authority control
Sesiidae
Moths described in 1789
Moths of Europe
Taxa named by Moritz Balthasar Borkhausen