Cranidium gibbosum

(by Bruno Kneubuehler)

General Notes

• originally described by Burmeister (1838) as Diapherodes gibbosa
• other synonyms: Diapherodes serricollis (Westwood, 1843), Monandroptera gibbosa (Westwood, 1859), Bacteria clavigera (Redtenbacher, 1908), Phasmilliger gibbosus (Carrera, 1960)
• this species has been collected in Petit-Saut (French Guyana), introduced to Europe and bred for the first time by phasmid breeders of the GEP (Groupe d'Etude des Phasmes)
• since then new culture stock of this species has been imported on other several occasions

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Origin

• the exact origin of the present culture stock is not known - but most probably from French Guyana

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Female

• big, bulky phasmids
• thorax and abdomen are stongly broadened - this gives them a somewhat leave-like appearance
• body length is 13 - 16 cm long
• colouration is a bright light green or yellow-green on the upper side, and a dark green on the underside
• the thorax' upper side has several yellowish bumbs with a dark brown peak
• the number of these bumps is variable
• not winged

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Male

• slime phasmids, especially when compared to the females
• morphological differences between males and females are very remarkable
• body length is about 9 - 9,5 cm
• colouration:  bluish-green (thorax upper side), glossy green (thorax lower side) and several brown and white areas
• they have fully developed wings, which to flutter for a shot distance

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Nymphs

• nicely coloured, orange-brown with yellow
• antennae have a white tip and are about as long as the fore legs
• they are already quite big on hatching. Therefore the hatching box should be big enough, otherwise some nymphs will be badly crippled
• by L2, males and females can be distinguished quite easily. First the poculum of  the males is already clearly visible, and the thorax and abdomen of the females is already a bit broader than in males

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Eggs

• about 4,5 x 3 mm
• spherical
• dark brown mottled
• matt

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Food Plants

• the natural food plant of this species seems to be Vismia Guianensis(relatively closely related to the genus Hypericum)
• nymphs (from L1) and adults feed on bramble (Rubus sp.) easily
• I feed my culture of this species exclusively on bramble (Rubus sp.)
• if bramble is being fed, then in springtime one should offer old leaves (from the previous year) for as long as possible. They do not accept well (if at all) the new leaves
• other food plants: Salal (Gaultheria shallon), Buche (Fagus sylvatica), raspberry (Rubus idea), oak (Quercus sp.), Hypericum, Strawberry (Fragaria sp.)
• cut away the edges of the leaves for the freshly hatched nymphs

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Defensive Behaviour

• especially the males can behave themselves very hectically. When they feel threatended (like when the cage is being opended) they let themselves fall to the ground, where they jiggle about frantically for a short time
• when females feel threatended (especially when being touched), they often also try to let themselves fall to the ground too. But as the females are quite bulky creatures, one should try to avoid this to happen - otherwise they can harm themselves

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Breeding Notes

• a wonderful species, with a very interesting sexual dimorphism
• it needs good skills and experience to breed this species successfully
• incubation: HH-incubation method on slightly damp sand yields good hatching ratios (50% and more in my culture)
• incubation time at room temperatures (20 - 23°C) is about 4 - 5 months
• nymphs hatch during the day - often in the early morning
• therefore the eggs should be exposed to a day-night cycle during the incubation, so that they can hatch at the appropriate time
• keep the nymphs in a cage with good ventilation
• freshly hatched nymphs should be kept very humid until they have started to feed nicely, if needed one can also spray them lightly (!) with water
• cut away the edges of the leaves for the freshly hatched nymphs
• keep the nymphs seperate from the adults
• especially older female nymphs should not be kept in a crowded cage. Otherwise they will nibble on eachother (especially on their broadened abdomen)
• take care that the humidity does not drop too low
• a constantly wet paper towel on the bottom of the cage helps raising humidity
• make shure that nymphs, which are about to undergo their adult moult, do not find places in the cage which would not offer them enough space beneath to moult successfully. Especially the females of this species have a strong tendency to find the lowest twigs for their final moult
• males will be adult after about 3 - 3,5 months (at room temperatures), females after 4,5 months
• adult females appear rather voracious when feeding, they can eat quite a lot too
• if there is not enough food plants in the cage, then the abdomen of many females will have bite marks - as it happens with Phyllium species
• females start to lay eggs after about 3 weeks
• 25 - 30 eggs per week
• they fling the eggs with a lot force - and the eggs can break when they are flinged directly against something very hard (like glass). Therefore using a netting cage might be advisable....