The longest known phasmid and longest extant insect in the world is the female of the Giant Stick-Insect Phobaeticus chani Bragg, 2008 (Clitumninae: Pharnaciini) from Sabah, Borneo. The holotype specimen in the Natural History Museum London (BMNH) has a body length of 357 mm and measures an amazing 566 mm (the fore tarsi are incomplete) with the fore legs stretched out straight.
The second longest known phasmid in means of overall-length is the Malayan Giant Stick-Insect Phobaeticus serratipes (Gray, 1835), with a female collected in November 1994 in the Tasek Chini National Park, Peninsular Malaysia measuring 555 mm from the tip of the fore tarsi to the apex of the abdomen. The body-length of this specimen however only was 278.0 mm. In means of body-length the second longest insect in the world is represented by Phobaeticus kirbyi Brunner v. Wattenwyl, 1907, the holotype specimen in the the Natural History Museum London (BMNH) measuring 317 mm. A female of the same species from the Temburong District in Brunei measured an overall-length of 546.0 mm, and hence is the third longest insect in means of overall-length. The third longest insect in means of body-length is the female of Phobaeticus magnus Hennemann & Conle, 2008 found in Thailand and Peninsular Malaysia with up to 315 mm.
The world's longest known extant male insect is Phryganistria heusii (Hennemann & Conle, 1997) from Northern Vietnam with a maximum recorded body-length of 250.5 mm and an overall-length of over 470 mm.
The Top-Ten of the world's longest insects (body-length):
1. Phobaeticus chani Bragg, 2008 [Clitumninae: Pharnaciini], Borneo (Sabah): 357.0 mm
2. Phobaeticus kirbyi Brunner v. Wattenwyl, 1907 [Clitumninae: Pharnaciini], Borneo: 317.0 mm
3. Phobaeticus magnus Hennemann & Conle, 2008 [Clitumninae: Pharnaciini], Thailand & Peninsular Malaysia: 315.0 mm
4. Phobaeticus redtenbacheri (Dohrn, 1910) [Clitumninae: Pharnaciini], Borneo (Sabah): 300.0 mm
5. Ctenomorpha gargantua Hasenpusch & Brock, 2006 [Phasmatinae: Phasmatini], Australia: ca. 300 mm
6. Phryganistria heusii Hennemann & Conle, 1997 [Clitumninae: Pharnaciini], N-Vietnam: 293.0 mm
7. Tirachoidea jianfenglingensis (Bi, 1994) [Clitumninae: Pharnaciini], N-Vietnam: 280.0 mm
8. Phobaeticus serratipes (Gray, 1835) [Clitumninae: Pharnaciini], Peninsular Malaysia, Singapore & Sumatra: 278.0 mm
9. Acrophylla titan (Mac Leay, 1827) [Phasmatinae: Phasmatini], Australia: 270.0 mm
10. Macrophasma lyratum (Redtenbacher, 1908) [Stephanacridini], New Guinea: 268.0 mm
There are several other species whose females achieve body-lengths of 25 cm and more. The following is a list of the largest species of certain zoogeographical regions or islands:
Afrotropis: Bactrododema hippotaurum (Karsch, 1896) [Palophinae], East-Afrika (Malawai): 263.0 mm
Madagascar: Achrioptera punctipes punctipes (Audinet-Serville, 1838) [Achriopterini]: 258.3 mm
Sri Lanka: Phobaeticus hypharpax (Westwood, 1859) [Clitumninae: Pharnaciini]: 236.0 mm
Indonesia: Nesiophasma plateni (Dohrn, 1910) [Stephanacridini], Talaud Islands: 263.0 mm
Philippines: Phobaeticus philippinicus (Hennemann & Conle, 1997) [Clitumninae: Pharnaciini): 247.5 mm
Fiji: Hermarchus pythonius (Westwood, 1859) [Stephanacridini]: 242.0 mm
New Zealand: Argorsarchus horridus (White, 1846) [Phasmatinae: Acanthoxylini]: 150.0 mm
Neotropis: Otocrania aurita (Burmeister, 1838) [Cladomorphinae: Cladomorphini], Brazil: 245.0 mm
Caribbean: Diapherodes gigantea (Gmélin, 1789) [Cladomorphinae: Hesperophasmatini]: 194.0 mm
Nearctis: Megaphasma dentricus Stal, 1875 [Diapheromeridae: Diapheromerini], U.S.A.: 150.0 mm
The largest representatives of the "Leaf-Insects" (Family Phylliidae) is the well-known Malayan Phyllium (Pulchriphyllium) giganteum Hausleithner, 1984 from West Malaysia. Females reach body-lengths of up to 115 mm, males measure up to 82 mm. Hence, both sexes are considerably larger than most other species. Only the females of Phyllium mamasense Größer, 2008 from South-Sulawesi and Ph. westwoodii Wood-Mason, 1875 are almost as long as Ph. giganteum measuring up to 100 mm.
The shortest so far known phasmid is the male of Grylloclonia minima (Zompro, 1998) from the Andes of South Ecuador with a body length of only 17.5 mm (Xerosomatinae: Xerosomatini). The female of Miniphasma prima (Zompro, 1999) from the central highland of Sri Lanka (Subfamily Pachymorphinae) also measures 17.5 mm; the male of this species is presumed to be even shorter. The females of several Grylloclonia-species from the South American Andes are real dwarfs, the female of Grylloclonia papallacta (Giglio-Tos, 1910) for instance measures only about 23 mm.
The shortest phasmids of the Oriental Region are the males of Ommatopseudes harmani (Brock, 1995) and Ommatopseudes paradoxus Günther, 1942 (Aschiphasmatinae: Aschiphasmatini) each with a recorded body-length of 18 mm. Furthermore, most representatives of the genera Dares Stal, 1875, Planispectrum Rehn & Rehn, 1939 and Pterobrimus Redtenbacher, 1906 (Heteropterygidae) hardly measure 30 mm. The smallest known phasmid of the african continent is the male of Clonaria parva (Zompro, 1998) from Kenia, with a body-length of only 30 mm (Pachymorphinae: Gratidiini).
The smallest representative in the "leaf-Insects" (Family Phylliidae) is the male of Microphyllium spinithorax Zompro, 2001 from the Philippine island of with a body length of merely 24 mm.
In full egg-production the females of the well known "Green Jungle-Nymph" Heteropteryx dilatata (Parkinson, 1798; Subfamily Heteropteryginae) from Peninsular Malaysia can weigh up to 65g. With an estimated weight of up to 60g females egg-laying females of the New Guinean Extatosoma popa popa Stal 1875 are not much less. Very small, fragile and flying species in contrast may weigh less than 1g.
The Largest / Longest Eggs
The largest and heaviest eggs are those of the bulgy and spiny Haaniella echinata (Redtenbacher, 1906) from with a weight of up to 0.3g and a length of up to 12 mm. Other species of the genera Haaniella Kirby, 1904 and Heteropteryx Gray, 1835 (Subfamily Heteropteryginae) produce almost equally large and heavy eggs with lengths up to 10 mm. The eggs of some of these species are often boiled and eaten by locals in Borneo, because of the high degree of proteins contained and as a medicine against diarrhoea.
Amongst the longest known phasmid eggs are those of Asceles malaccae (Saussure, 1868; Subfamily Necrosciinae) from Peninsular Malaysia with an overall-length of up to 15 mm. They are however much more slender with a diameter of only about 2 mm and have the polar end produced into a long spine-like projection, which is used to draw the eggs into leaves or stems of the host-plant. The overall-length is furthermore only achieved thanks to the almost 2mm tall, conical operculum. It is also remarkable that such large eggs are produced by rather slender, stick-like females with a body-length of only 90-100 mm.
Another taxon with very long eggs is Medauromorpha from Vietnam. Those of Medauromorpha regina "Tay Yen Tu" are up to 16 mm long. These are (so far) the longest known eggs, even without a long operculum or spine-like extension.
The Largest Number of Eggs
Females of the giant stick-insects Acrophylla titan (Mac Leay, 1827) and Anchiale briareus (Gray, 1834) from Northern Australia can produce a total of up to 2.500 eggs during their life-time (Phasmatinae: Phasmatini). A total of 2.052 eggs have been recorded for a captive reared female Acrophylla titan. A captive reared female of the Philippine Hermarchus leytensis (Zompro, 1997) was recorded to have produced 2.375 eggs.
Females of Anchiale briareus (Gray, 1834) from Queensland can lay up to 21 per day! The main reason for this great number laid per day is the remarkably small size of the eggs (length only 3.5 mm) in relation to the rather large insects, which reach body lengths of up to 17 cm. In contrast, most species of the subfamily Dataminae, e. g. in the genera Dares Stal, 1875, Planispectrum Rehn & Rehn, 1939 or Pylaemenes Stal, 1875, merely produce one or two eggs per week. In these cases the eggs are remarkably large if compared to the insects.
The Longest Copulation
Males of the genus Anisomorpha Gray, 1835 (Pseudophasmatinae: Anisomorphini) usually remain on the back of "their" female for an entire life-time, being carried around by the much larger female. The copulation is not even interrupted during oviposition. Sometimes, when the female dies first, males are observed to remain attached to the dead body of their female for several more hours or even days. In general, the copulation only takes a few hours in the Phasmatodea.
The Highest Distribution
Species of the genus Monticomorpha Conle & Hennemann 2002 (Pseudophasmatinae: Anisomorphini) in particular live in highly mountainous biotopes in the Andes of South America. They are characterized by their very small size and mostly black colouration, hence are very well adapted to the extreme climate of the habitats they live in. The highest record of the entire Phasmatodea is represented by the strikingly black and yellow banded Monticomorpha flavolimbata (Redtenbacher, 1906), which occurs on the Volcano Cotopaxi (N-Ecuador) in altitudes up to 5.000 m. These highest dispersals of M. flavolimbata are situated along the snow-border where the insects endure the night-frosts under stones and warm themselves up in the sun during the day.
The Longest Lived
The highest recorded age was achieved by a wild-caught female of Haaniella scabra (Redtenbacher, 1906; subfamily Heteropteryginae) from Mount Kinabalu (Sabah, Borneo). Imported to Germany, this insects survived for over 5 years in the laboratory and readily accepted various alternative food-plants including bramble (Rubus spp.) or oak (Quercus spp.). Kim D´Hulster (Belgium) has reported rearing a female Dares verrucosus Redtenbacher, 1906 (subfamily Dataminae), still alive after hatching five years earlier.
In general, representatives of the family Heteropterygidae have the highest live expectancy amongst all Phasmatodea. Almost all species live at least for one year after their final skin-shed. Many phasmids however, but in particular males of small flying species (e.g. subfamily Necrosciinae) or of the "Leaf Insects" (genus Phyllium Illiger, 1798), live no more than a few weeks as adults.
Answering the question which is the rarest phasmid is difficult to answer. The most popular and endangered species is the "Lord Howe Island Stick-Insect" or "Tree Lobster" Dryococelus australis (Montrouzier, 1855; subfamily Eurycanthinae), which was added to the red list of seriously endangered species in 2002. This remarkable, almost 13 cm long species was formerly very abundant on Lord Howe Island,,an island some 500 km off the Australian east-coast, with as many as 68 individuals found inside a single cavity of a tree trunk. They were usually found hiding in tree holes during the daytime and apparently only left the holes at night to feed.
In the 1920s Black Rats (Rattus rattus, Fam. Murinae) were introduced by European settlers which had a strong destructive effect on the islands fauna and exterminated D. australis. The "Lord Howe Stick-Insect" was since thought to be extinct, until freshly dead specimens were found by climbers on Balls Pyramid during the 1960's. In February 2001, a survey of Balls Pyramid, a volcanic spire 23 km southeast of Lord Howe Island, which is free of rats, discovered a small population of D. australis on a precipitous terrace 65 m above sea level. Three live specimens were located feeding on an endemic tea-tree Melaleuca howeana (Fam. Leguminosae). All evidence indicated that the species was confined to this single small terrace measuring only 30 m x 6 m. A second survey, in March 2002, located a total of 17 D. australis dispersed on six of these shrubs at the same locality. Two live couples were captured and brought to the Australian mainland in order to breed D. australis in captivity and re-introduce it to Lord Howe Island, which however deserves a systematic rat eradication program to be implemented and successful.
It is also worth mentioning the obviously extinct species Xenomaches incommodus (Butler, 1876) from Rodrigues Island in the Indian Ocean. This strikingly green species of the subfamily platycraninae with bright red antennae appears to have been quite commonly encountered at least since the late 19th century on the endemic palm Latania verschaffeltii. X. incommodus has probably become extinct with the disappearance of it's host-plant on Rodrigues Island.
Certainly, due to the increasing destruction of their natural habitats numerous other species may have become endangered or already extinct since they were last recorded. This in particular the case for those highly specialized species which are restricted to small and fragile biotopes, e.g. in den Andes or on small islands.
Pest-like often seasonal occurrences of various phasmid species and considerable damage to certain plants are frequently reported from different parts of the world. Due to their abundance some species are even treated as pests with agricultural importance. A few examples are from different geographical regions are given below:
Polynesia: There are reports from the 1800s of Graeffea crouanii (Le Guillou, 1841; subfamily Platycraninae) causing such dreadful devastation in coconut plantations throughout Fiji and Tuvalu that food was scarce. Systematic destruction became necessary but it is not sure how true are the remarks that cannibalism in some of the islands was due to the want of food caused by the ravages of G. crouanii!
Australia: Frequently outbreaks of the three species Didymuria violescens (Leach, 1814), Podacanthus wilkinsoni Mac Leay, 1881 and Anchiale austrotessulata Brock & Hasenpusch, 2008 are reported, which usually occur in cycles, with a two year generation period. Didymuria violescens in particular causes considerable defoliation in the mountain forests of New South Wales and Victoria, with some 650 square miles of Eucalyptus forest almost completely destroyed in 1963.
USA: A two year cycle of outbreaks is also observed in some Nearctic species, which mainly concerns to Diapheromera femorata (Say, 1824) in the eastern United States and Megaphasma dentricus Stal, 1875 in Texas and Arkansas. Both species frequently cause considerable damage predominantly in Oak forests. The insects may sometimes be so numerous that the dropping of eggs and excrements sounds like rain! Diapheromera femorata usually makes two generations per year.
China: Numerous species in China are locally very abundant and can occur in pest-like numbers. Since the 1970's considerable defoliations caused by phasmids were recognized in many provinces. Some have even become pests of serious importance for agriculture in China. The following summarizes a few bad cases. In March and April 2005 Baculonistria alba (Chen & He, 1990; subfamily Clitumninae) has caused serious damage in the most important green-shelter of Yangtze River, Three Gorges Area Chongqing with an area of about 800 ha of Cupressus funebris (Fam. Cupressaceae) almost completely defoliated. About 40 ha of the trees were dead and an average of 120 specimens were counted per tree. In early May the outbreak was controlled by application of pesticides. In 1989 and 1990 up to 3500 ha of Castanopsis fissa (Fam. Fagaceae) were damaged by a pest of Micadina yingdensis Chen & He, 1992 (subfamily Necrosciinae). Some 850 ha of the trees were entirely defoliated or dead in 1990, which has caused an economic damage due to the loss of timber of approximately 560.000 US$. More than 450 specimens were encountered in a single three year old three with less than 100 leaves. Similarly serious damage was caused by Ramulus minutidentatus (Chen & He, 1994; Unterfamilie Clitumninae) between 1998 and 2001 in Tongua city (Jiling Province). An average of 2000-5000 insects were encountered in a single Tilia mandshurica (Fam. Tiliaceae) and random analysis of fallen leaf-litter on the ground beneath the affected tree, has shown the density of dropped eggs to be 1000-3000 per square meter!
Some years ago two phasmid species have developed pest-like in the greenhouses of the well-known Botanical Gardens in Munich (Germany) and have caused considerable damage on the old and unique plants housed there. The two species concerned were Sipyloidea sipylus (Westwood, 1849) and Ramulus artemis (Westwood, 1859), both of which are known to be extremely productive in European cultures. It is presumed that the insects were either released by a someone or were introduced accidentally. Due to the defoliation of rare plants pesticides had to be applied to control the pest.
The Most Dangerous
Phasmids are generally harmless, but several Phasmatodea have developed active, either mechanical or chemical ways, of sufficiently defending themselves against predators.
Mechanical defense: The males of the genera Eurycantha Boisduval, 1835 or Dryococelus Gourney, 1947 (subfamily Eurycanthinae) have developed the perhaps most impressive and spectacular weapons for active defense against predators. The hind femora are massively thickened and enlarged, equipped with strong musculature and on the underside armed with a large and very strong back-curving spine. The corresponding tibiae are also armed with numerous sharp spines on their underside. These armed hind-legs are aggressive are used to pinch the predator and can cause serious injuries. In case of a human hand, the length of the femoral spine and strength of the musculature is plenty enough to draw the spine through the flesh right until the bone!
Chemical defense: Quite a number of species, mostly in the families Aschiphasmatidae and Pseudophasmatidae or the subfamily Platycraninae, have developed effective chemical defense mechanisms in form of prothoracic glands. These enable the insects to squirt an irritating and strongly smelling milky spray. This causes considerable harm or even temporary blindness when it gets in contact with the eyes. Oreophoetes Rehn, 1904 (subfamily Diapheromerinae) merely extracts the defensive fluid dropwise, whereas it is actively sprayed over a distance of up to 50 cm in e.g. Megacrania-species (subfamily Platycraninae). In this latter genus the smell of the secretion remarkably resembles that of peppermint. Representatives of the New World Pseudophasmatidae (e.g. Anisomorpha Gray, 1835 or Peruphasma Conle & Hennemann, 2002) strongly disperse their secretion. The chemical composition of these defensive secretions is currently being studied in more detail and some have already been given names (e.g. "Anisomorphal", "Peruphasmal" or "Parectadial").
The three first scientifically described Phasmid-species
The three first phasmid species were described in 1758 in the "Systema Naturae" by the famous Swedish scientist Carl von Linnaeus. These are:
1. Gryllus (Mantis) gigas Linnaeus, 1758 [= Phasma gigas (Linnaeus, 1758)]
2. Gryllus (Mantis) phtisicus Linnaeus, 1758 [= Pseudophasma phtisicum (Linnaeus, 1758)]
3. Gryllus (Mantis) siccifolius Linnaeus, 1758 [= Phyllium (Phyllium) siccifolium (Linnaeus, 1758)
Here we want to show you some curious, strange or funny things from the world of Stick and Leaf-Insects. Just as in our world, failures, misunderstandings and confusion happen in their world as well...
Below is a photo which gives a view into an over-crowded breeding cage. How many phasmids can you spot on the photo?
If different phasmid species are kept together in one cage it may happen that different species or even representatives of distinct genera will mate with another! These "copulations" however are not successful and do not produce hybrids. In the wild such "foreign matings" are very rarely encountered.
Just as in human kind, some women appear to be more desired than others... On the picture below three males of Spinohirasea bengalensis (Brunner v. Wattenwyl, 1907) from Vietnam try to mate with a single female at the same time!
Gynandromorphism is the presence in one sex of characteristics belonging to the other sex. The portions belonging to either sex are variable, but are distributed along the length-axis of the insect usually with the left and right side dimorphic. Such abnormal insects are most spectacular in species in which males and females look very different (= sexual dimorphism), e.g. having a different colour of wings only present in one sex. In such cases a wing may only be present on one side of the insect, whereas it is strongly reduced or lacking on the opposite side!! Gynandromorphism is known to occur in e.g.: Heteropteryx dilatata (Parkinson, 1798), Diapherodes gigantea (Gmélin, 1789), Oreophoetes peruana (Saussure, 1868), Clonopsis gallica(Charpentier, 1845),Carausius morosus (Sinéty, 1899) und Ramulus artemis (Westwood, 1859), Extatosoma tiaratum (Mac Leay, 1826) and Phyllium bioculatum (Gray, 1832)
The following three pictures show a gynandromorph specimen of Diapherodes gigantea aus Grenada, raised in captivity by Mieke Duytschaever (Belgium) in 2008. This insect shows mostly male characteristics on the left, while there are obvious female characteristics on the right, e.g. the green colouration on the right and presence of a fully developed hind wing on the left only.