Panorpa Cognata
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''Panorpa cognata'' is a species of
scorpionfly Mecoptera (from the Greek language, Greek: ''mecos'' = "long", ''ptera'' = "wings") is an Order (biology), order of insects in the superorder Holometabola with about six hundred species in nine Family (biology), families worldwide. Mecopterans a ...
belonging to the family
Panorpidae The Panorpidae are a family of scorpionflies containing more than 480 species. The family is the largest family in Mecoptera, covering approximately 70% species of the order. Species range between 9–25 mm long. These insects have four me ...
.


Subspecies

Subspecies In Taxonomy (biology), biological classification, subspecies (: subspecies) is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (Morphology (biology), morpholog ...
include: *''Panorpa cognata cognata'' Rambur, 1842 *''Panorpa cognata ghilianii'' MacLachlan, 1869 *''Panorpa cognata osellai'' Willmann, 1976


Distribution and habitat

This species can be found across the British Isles (but not Ireland), western
Europe Europe is a continent located entirely in the Northern Hemisphere and mostly in the Eastern Hemisphere. It is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west, the Mediterranean Sea to the south, and Asia to the east ...
into
Russia Russia, or the Russian Federation, is a country spanning Eastern Europe and North Asia. It is the list of countries and dependencies by area, largest country in the world, and extends across Time in Russia, eleven time zones, sharing Borders ...
and Northern Asia (excluding China).P.H. Ward. 1983. Scorpion-flies of the ''Panorpa cognata''-complex in the western palaearctic region (Mecoptera). Journal of Natural History, 17(4), 627-645. They usually inhabit hedges and woods.


Description

''Panorpa cognata'' has a fore-wing length ranging between 10 and 15mm, and are orange-brown in colour, sometimes with black colouration along the posterior margin, the base of the antennae, sometimes the pronotum. True to their name, males have an oval-shaped genital bulb, resembling that of a scorpion's
stinger A stinger (or sting) is a sharp organ found in various animals (typically insects and other arthropods) capable of injecting venom, usually by piercing the epidermis of another animal. An insect sting is complicated by its introduction of ve ...
.Engqvist, L. & Sauer, K.P. 2002. Amorous scorpionflies: causes and consequences of the long pairing prelude of ''Panorpa cognata''. Animal Behaviour, 63, 667–675.Esben-Petersen, P. 1921. Mecoptera: Collections Zoologique Du Baron Edm. de Selys Longchamps: Catalogue Systématique et Descriptif. Hayez, Impr. des Académies. Bruxelles 1921 In these slender, small insects the back part of the head (occiput) is reddish, while in all other species it is usually black. Wings are membranous with black markings. The abdomen is black and yellow striped with an orange extremity. In males the sixth abdominal segment is square and appendages are divergent.Insects-chinery. Pag 108
/ref>


Biology

Larvae and adults mainly feed on dead insects and carrion. Adults are visible from May to July.


As a model organism

''P. cognata'' has been used as a
model organism A model organism is a non-human species that is extensively studied to understand particular biological phenomena, with the expectation that discoveries made in the model organism will provide insight into the workings of other organisms. Mo ...
for investigating sexual selection; effects of conditions on female choice and male mating behaviours, cryptic sexual selection, and effects of multiple mates on
fecundity Fecundity is defined in two ways; in human demography, it is the potential for reproduction of a recorded population as opposed to a sole organism, while in population biology, it is considered similar to fertility, the capability to produc ...
and egg hatching. Female ''P. cognata'' are
polyandrous Polyandry (; ) is a form of polygamy in which a woman takes two or more husbands at the same time. Polyandry is contrasted with polygyny, involving one male and two or more females. If a marriage involves a plural number of "husbands and wives ...
, allowing females greater access to resources, in the form of salivary
nuptial gift Formally, a nuptial gift is a material presentation to a recipient by a donor during or in relation to sexual intercourse that is not simply gametes in order to improve the reproductive fitness of the donor. Often, such a gift will improve the fit ...
s from multiple mates, increased genetic variation in her offspring, and resulting in a greater success of eggs hatching compared to monandrous females Engqvist, L. (2006). Females benefit from mating with different males in the scorpionfly ''Panorpa cognata''. Behavioral Ecology, 17(3), 435-440.Engqvist, L. (2007). Nuptial gift consumption influences female remating in a scorpionfly: male or female control of mating rate?. Evolutionary Ecology, 21(1), 49 -61. Polyandry results in a high incidence of
sperm competition Sperm competition is the competitive process between Spermatozoon, spermatozoa of two or more different males to fertility, fertilize the same Egg cell, egg during sexual reproduction. Competition can occur when females have multiple potential m ...
, and males compete for the ability to mate with females. Male ''P. cognata'' do not compete directly, and do not guard or restrict females, but attract potential mates through
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; initiating copulation with a salivary nuptial gift following a premating display that can sometimes last hours in length. Condition of both female and male ''P. cognata'' ultimately play a role in a successful copulation.Engqvist, L. & Sauer, K. P. 2003. Determinants of sperm transfer in the scorpionfly ''Panorpa cognata'': male variation, female condition and copulation duration. Journal of Evolutionary Biology, 16, 1196–1204. Once copulation is initiated, sperm transfer is maintained at a constant, linear rate, indicating that longer copulation periods allow for the transfer of more sperm, however, individual males have significantly varying rates of sperm transfer. Copulation duration is directly linked to the size of the salivary nuptial gift presented to the female, with larger salivary gifts resulting in copulations of longer duration, and a greater number of sperm transferred.Engqvist, L. 2001. Strategic male mating effort and cryptic male choice in a scorpionfly. Proceedings of the Royal Society B Biological Sciences, 268(1468), 729-735. At the beginning of the breeding seasons, males are more particular in
mate choice Mate choice is one of the primary mechanisms under which evolution can occur. It is characterized by a "selective response by animals to particular stimuli" which can be observed as behavior.Bateson, Paul Patrick Gordon. "Mate Choice." Mate Choi ...
, choosing to expend more energy attracting and mating with females of good condition, while by the end of the breeding season, males are less picky towards female condition, and breed more indiscriminately.


Male reproductive investment

Investment in reproduction is costly for male ''P. cognata'', as they must “woo” females, and eventually produce a salivary mass to initiate copulation. Once copulation has begun, sperm transfer itself is costly, as well. Sperm is transferred into the female via a sperm pump, which has two thick muscles, one on either side of the pump. Nutrient availability during the
larva A larva (; : larvae ) is a distinct juvenile form many animals undergo before metamorphosis into their next life stage. Animals with indirect development such as insects, some arachnids, amphibians, or cnidarians typically have a larval phase ...
l stage affects adult body weight, and the development of the males' salivary glands. Males with restricted access to nutrients in larval stage have reduced mating success compared to those of good condition with access to greater amounts of nutrients in the larval stage.Engels, S. & Sauer, K. 2007. Energy beyond the pupal stage: Larval nutrition and its long-time consequences for male mating performance in a scorpionfly. Journal of Insect Physiology, 53(7), 633-638. Males of lower condition have less resources to produce nuptial gifts, resulting in smaller salivary masses, shorter mating duration, and less sperm transferred.Engqvist, L. (2009). Should I stay or should I go? Condition- and status-dependent courtship decisions in the scorpionfly ''Panorpa cognata''. Animal Behaviour, 78(2), 491-497. To counteract their poor condition, males tend to have a longer premating duration than those of higher condition. Males of higher condition tend to have shorter premating periods and larger nuptial gifts. Premating rituals do not always finish in successful copulation, females abandon the male courting her for better, more attractive mates. Male ''P. cognata'' regulate their mating investment according to the amount of sperm competition. Female ''P. cognata'' store sperm from each male she mates with, and each consecutive mate has the ability to assess how much sperm she is storing, thus down-adjusting the male's investment in copulation with a female who has more sperm stored.Engqvist, L. 2007. Male Scorpionflies Assess the Amount of Rival Sperm Transferred by Females' Previous Mates. Evolution, 61(6), 1489-1494.


Female reproductive investment

The condition of female ''P. cognata'', dictated by nutritional availability in the larval stage, is positively correlated with the number of sperm transferred during copulation, with males transferring sperm to females in good condition at a faster rate than they would transfer to females of poor condition. Females control the duration of copulation, which is directly affected by the size of the salivary nuptial gift provided by the male. The species, ''P. cognata'', benefits as a whole from the female mating with multiple males and ingesting multiple salivary nuptial gifts, as each salivary mass a female ingests has been shown to have, on average, a positive 8% increase on the number of eggs she lays.Engqvist, L. 2007b. Nuptial food gifts influence female egg production in the scorpionfly ''Panorpa cognata''. Ecological Entomology. 32(3), 327 -332. The duration of copulation impacts the female's length of time between rematings; longer copulations result in a longer period between matings.


References

{{Taxonbar, from=Q3362416 Mecoptera Insects of Europe Insects described in 1842