Cyclommatus metallifer is a species of stag beetle in the family Lucanidae.[1] There is sexual dimorphism within the species. Males are generally larger in size and have enlarged mandibles. It is named for its metallic coloration, which ranges in color and may be varying levels of black, brown, or gold.[2] This species is notably easy to maintain, making it a useful species for scientific study.[3] Additionally, it has been kept as an exotic pet.
C. metallifer exhibits extreme sexual dimorphism, where males are larger than females and have long mandibles. These mandibles are important for sexual selection, and males use them in competition. To compensate for the weakened bite force caused by their long mandibles, males of this species have larger head muscles than females.[4] Because their entire head morphology is specialized for sexual selection, both the head and mandibles can be considered key components of their armaments. Because their bites are so powerful, their mandibles are adapted to resist against bending and torsion.[5] They also have large teeth along their jaws, which are used to improve their grip on rivals.
The size of males varies greatly, with certain subspecies ranging from 26 to 100 millimetres in length.[2] The females are subject to much less variation, typically ranging from 22 to 28 millimetres in length.
To avoid breaking their jaws when biting, male C. metallifer have a high density of mechanoreceptors on their mandibles.[6] These act as sensors to allow C. metallifer to control the force of their bite, which protects their jaws despite having powerful bite muscles. Mechanoreceptors are especially dense around the tips of the mandibles, where the most stress is present.
C. metallifer and all its subspecies are found in Indonesia, primarily on the Maluku Islands and Sulawesi.[7] They prefer a tropical to subtropical environment. They feed on sap, which they obtain by scratching plants with their mandibles.[2] Additionally, they may also gather flowers and fruit.
C. metallifer is characterized by large mandibles in the male. Mandible growth is regulated by juvenile hormone, which controls many aspects of insect growth.[8] Exact mandible size varies and is primarily determined by nutrition in the larval stage. There is a relationship between body size and the length of mandibles, which is a heritable trait.[3] While the actual size of the mandibles is more dependent on nutrients, this relationship between body size and mandibles is determined by genetics.
C. metallifer has been used in genetic studies to determine the genes involved in its sexual dimorphism.[9] Because the sexual dimorphism in this species is so extreme, it is useful for determining the development of these traits. The doublesex gene regulates the differences between males and females.[10] While juvenile hormone is present in both males and females, doublesex influences the expression of this hormone.
The large mandibles in C. metallifer males hinder their ability to move. Their ability to run is reduced, making flight especially important for covering long distances. Males must work harder than females to fly because of the weight of their mandibles.[11] This creates an upper limit on the potential weight of their mandibles. However, variation in both size and shape of mandibles has minimal impact on flight. Mandible size is negatively correlated with wing size, which limits the flying ability of this species.[12] Therefore, their mobility is overall low, which is a significant cost associated with their mandibles.
The enlarged mandibles of C. metallifer are important for sexual selection. Although individuals with larger mandibles are more desirable mates and better competitors, having large mandibles has several trade-offs in terms of their stability and locomotion.[13] Males compete for mating opportunities using their mandibles. Both mandible size and bite force are important in fights. Size is a visible trait that is positively correlated with fighting ability, making mandible size an example of honest signalling in this species.[14] Because the development of large mandibles involves numerous investments and trade-offs, there is an upper limit to their size.
Competition between males takes the form of several interactions. These include jousting with their mandibles and forcefully biting, concluding with the loser being thrown off the tree and losing access to potential mates.[14] Larger mandibles are advantageous in all of these interactions, and only males that are nearly evenly matched will advance past the early stages of competition.
Males will use mate-guarding behaviour to prevent females from mating with other males.[2] This involves chasing away other males and protecting resources such as sap with territorial fights.[15]
These six subspecies belong to the species Cyclommatus metallifer:[2]
Cyclommatus metallifer is a species of stag beetle in the family Lucanidae. There is sexual dimorphism within the species. Males are generally larger in size and have enlarged mandibles. It is named for its metallic coloration, which ranges in color and may be varying levels of black, brown, or gold. This species is notably easy to maintain, making it a useful species for scientific study. Additionally, it has been kept as an exotic pet.
Cyclommatus metallifer es una especie de coleóptero de la familia Lucanidae. Presenta las siguientes subespecies:
Habita en las Célebes y las Molucas septentrionales (Indonesia).[1][2]
Cyclommatus metallifer es una especie de coleóptero de la familia Lucanidae. Presenta las siguientes subespecies:
Cyclommatus metallifer aeneomicans Cyclommatus metallifer finae Cyclommatus metallifer isogaii Cyclommatus metallifer metallifer Cyclommatus metallifer otanii Cyclommatus metallifer sangirensisCyclommatus metallifer is een keversoort uit de familie vliegende herten (Lucanidae). De wetenschappelijke naam van de soort is voor het eerst geldig gepubliceerd in 1835 door Boisduval.[1]
Bronnen, noten en/of referenties
Cyclommatus metallifer er en bille som hører til familien hjortebiller (Lucanidae) i gruppen skarabider (Scarabaeoidea). Arten utmerker seg ved ekstremt lange kjever hos hannene.
En middelsstor til meget stor (hannen 26-86 millimeter lang), metallisk farget hjortbille. Farge er svart med en grønnlig eller bronseaktig metallisk glans. Arten er nokså variabel i størrelsen, hos hannen er kjevene forholdsvis større jo større hannen er (allometrisk vekst). Store hanner har lange mandibler som er omtrent like lange som resten av dyret. Disse har oftest en innoverrettet tann litt innenfor midten, og er fint sagtakkede i spissen. Antennene er ganske lange og tynne, omtrent så lange som hodets bredde. Pronotum utvider seg forover. Dekkvingene er blanke uten synlig punktering. Beina er slanke, lårene ofte rødlige. Hunnen er mye mindre enn hannen, uten forstørrede kjever, ofte mørk på farge, i motsetning til hannen er kroppen tydelig og tett punktert.
Larvene utvikler seg i råtne trestammer.
Arten lever i Sørøst-Asia (Molukkene og Sulawesi).
Cyclommatus metallifer er en bille som hører til familien hjortebiller (Lucanidae) i gruppen skarabider (Scarabaeoidea). Arten utmerker seg ved ekstremt lange kjever hos hannene.
Cyclommatus metallifer là một loài bọ cánh cứng trong họ Lucanidae. Loài này được BOISDUVAL mô tả khoa học năm 1835.[1]
Cyclommatus metallifer là một loài bọ cánh cứng trong họ Lucanidae. Loài này được BOISDUVAL mô tả khoa học năm 1835.
メタリフェルホソアカクワガタ (Cyclommatus metallifer) は、節足動物門昆虫綱甲虫目クワガタムシ科に属するクワガタムシの一種。
ホソアカクワガタ属の他の大型種と同様に、極端な性的二型と、時として体長の半分以上に達する雄個体の長大な大顎が大きな特徴である。このような体型は、細い枝を主な生活場所として餌場や雌を奪い合う本種雄の生活スタイルに向いていると考えられている。スラウェシ島とその周辺の島々の低地に生息し、低温を好む傾向があるホソアカクワガタ属の中では比較的高温への適応力がある。飼育・繁殖が比較的容易なため、愛好家の間に広く普及している。 また、本種を用いた発生学的な研究も行われており、クワガタの大顎発達をもたらす内分泌メカニズムに関する研究や性特異的な大顎発達を制御する遺伝子に関する研究では本種が材料として使われている。
生息する島によって変異がみられ、以下のような亜種に分けられる。
掛け合わせ実験によると、このペレン島産に見られるブルー光沢を伴う濃紺の体色は、常染色体上の一遺伝子座における二つの対立遺伝子により制御されていると示唆されている。 また生き虫での流通量も多く、大きくなり色彩変異が多く人気の亜種である。
本種の野外における学術的な生態観察報告はSuzuki 1996の一例のみである。 昼行性であり雌雄共に低木の新芽を傷つけて吸汁することが知られ、雌雄の交尾は主にこの摂食サイトで行われると予想されている。 典型的なメイトガード行動が観察されている。
本種は比較的簡単に飼育できるため、ホソアカクワガタの入門種とされている。一般にホソアカクワガタは高温を嫌うため飼育の際には注意を要するが、本種は概ね25℃程度までの高温への耐性を有する。雌個体は微粒子の発酵マットをケースに硬く詰めたものにも十分産卵するが、産卵材を使用する場合は手で簡単にほぐれる程度にまで腐食の進んだものを使うとよい。幼虫も丈夫なので羽化させることは難しくないが、雌雄各々の幼虫が羽化までに要する期間が異なるので、累代飼育のためには羽化のタイミングのずれに注意を要する。♀が大抵早く羽化して♂がそれに間に合わないことが良くあるパターンだが、これを避けるために♂幼虫を高温飼育することで早めに羽化させ羽化時期をあわせる方法や、雌雄の幼虫を同一容器または各々の入った容器を接触させた状態で飼育する方法などが知られている。後者の方法は、幼虫が互いに微弱な振動を起こしたり感じ取ったりすることで互いの位置・性別・生育段階等を把握しているという説に基づく。
ペレン島産
カシルタ島産
スラウェシ島産
Suzuki T. 1996, Some ecological notes of Cyclommatus metallifer in Sulawesi, Indonesia: Adult feeding habits and possibility of guarding behavior in stag beetles. Gekkan-Mushi 305:16–19
Gotoh et al. 2011, Juvenile Hormone Regulates Extreme Mandible Growth in Male Stag Beetles. PLoS ONE 2011 6(6): e21139
