How to differentiate male and female nymphs

At times it would be a great help, if phasmid breeders would be able to distinguish between male and female nymphs - for different reasons. For example one wants to limit the number of nymphs, yet wants to be sure that there is a good number of males and females. Or we have just a few nymphs and wanna take special care if there are only very few male or female nymphs.

Luckily this is possible, and actually not difficult. On the morphological level, the primary sexual characteristics are already presend even at the first nymphal stage (L1) just after hatching. And for number of species it is easy to recognize this in L1, even to the naked eye. This is especially true for big and bulky species (like Phryganistria,Achrioptera, Haaniella).

Then again, in other species it is somewhat difficult to see these differences in L1, unless one has a microscope at hand. This often the case for thin species with small nymphs (like most Necrosciinae). For such species one has to wait until L3 or even L4 before these difference between male and female nymphs become apparent.

Below you find the informations on how to distinguish male and female nymphs for different species:

Achrioptera fallax "Orangea"

The differences are easily recognizable in the 1st instar (commonly called L1):

  • The developing poculum of male nymphs is easily recognizable ventrally on the 9th abdominal segment as a small "hump"
  • Female nymphs lack this "hump", yet with a good magnifying glass the developing gonapophyses and subgenital plate are visible ventrally on the 8th abdominal segment
Achrioptera fallax L1.
Achrioptera fallax L1.

And in the 3rd instar stage (L3), this differences are even more pronounced:

  • The developing poculum of male nymphs is now quite a big and obvious "hump"
  • The developing subgenital plate of female nymphs already reaches to the middle of the 10th abdominal segment
Achrioptera fallax L3.
Achrioptera fallax L3.

Anchiale sp. "Buru"

The differences are easily recognizable in the 3rd instar (L3):

  • The developing poculum of male nymphs is visible ventrally on the 9th abdominal segment as a small "hump"
  • Female nymphs lack this "hump", but with a good magnifying glass the developing gonapophyses and subgenital plate are visible ventrally on the 8th / 9th abdominal segment
Anchiale buruense L1.
Anchiale buruense "Buru" L1. Ventral view.
Anchiale buruense L1.
Anchiale buruense "Buru" L1. Lateral view.

Autolyca sp. "Tegucigalpa, red"

The differences are easily recognizable in the 1st instar (L1):

  • The developing poculum of male nymphs is visible ventrally on the 9th abdominal segment as a small "hump"
  • Female nymphs lack this "hump", but with a good magnifying glass the developing gonapophyses and subgenital plate are visible ventrally on the 8th / 9th abdominal segment
Autolyca sp. L1.
Autolyca sp. L1. Lateral view.

Epidares nolimetangere

The differences are easily recognizable in the 1st instar (L1). Male nymphs have a small hump (which is the developing poculum) at the ventral side of the 9th abdominal segment, whilst the female nymphs lack this hump on the 9th abdominal segment.

Epidares nolimetangere L3.
Epidares nolimetangere L3. Ventral view.

Eurycnema versirubra "Timor"

The differences are also easily recognizable in the 1st instar (L1). Male nymphs have a small hump (which is the developing poculum) at the ventral side of the 9th abdominal segment, whilst the females lack this hump on the 9th abdominal segment.

Eurycnema versirubra Timor L1.
Eurycnema versirubra "Timor" L1. Ventral view.

Heteropteryx dilatata

The differences are easily recognizable in the 2nd instar (L2):

  • The developing poculum of male nymphs is very distinct ventrally on the 8th abdominal segment
  • Female nymphs have a much longer supraanal plate (dorsally, end of abdomen)
  • These differences are also well visible in L1
Heteropteryx dilatata L2. Ventral view.
Heteropteryx dilatata L2. Ventral view.
Heteropteryx dilatata L2. Dorsal view.
Heteropteryx dilatata L2. Dorsal view.

Phryganistria bachmaensis "Bach Ma"

The differences are easily recognizable in the 3rd instar (L3):

  • The developing poculum of male nymphs is visible ventrally on the 9th abdominal segment as a small "hump"
  • Female nymphs lack this "hump", but with a good magnifying glass the developing gonapophyses and subgenital plate are visible ventrally on the 8th / 9th abdominal segment
  • These differences are also visible in L1, though less obviously (see Phryganistria sp. "Da Krong")
Phryganistria bachmaensis Tam Dao L3. Lateral view.
Phryganistria bachmaensis "Tam Dao" L3. Lateral view.
  • Furthemore, female nymphs in L3 have dark colored lobes on the sides of the 7. abdominal segment. These lobes are almost absent in male nymphs
  • And male nymphs in L3 have long, well developed lobes at the end of the 10th abdominal segment ("latero-posterior lobes")
Phryganistria bachmaensis Tam Dao L3. Dorsal view.
Phryganistria bachmaensis "Tam Dao" L3. Dorsal view.

Phryganistria sp. "Da Krong"

The differences are easily recognizable in the 1st instar (L1):

  • The developing poculum of male nymphs is visible ventrally on the 9th abdominal segment as a small "hump"
  • Female nymphs lack this "hump", but with a good magnifying glass the developing gonapophyses and subgenital plate are visible ventrally on the 8th / 9th abdominal segment
Phryganistria sp. Da Krong L3. Lateral view.
Phryganistria sp. "Da Krong" L3. Lateral view.

Phyllium celebicum "Sulawesi"

The differences are easily recognizable in the 3rd instar (L3):

  • The 7th abdominal segment's outer border is much wider in female nymphs than in male nymphs
  • Males nymphs abdomen is more pointed, while the female nymph's abdomen appears rather angular
  • With a magnifiying glass it is easily visible that male nymphs have a small hump (the developing poculum) at the ventral side of the 9th abdominal segment. And female nymphs have a developing subgenital plate and gonapophyses ventrally on the 8th abdominal segment
Phyllium celebicum Sulawesi L3. Ventral view.
Phyllium celebicum "Sulawesi" L3. Ventral view.
Phyllium celebicum Sulawesi L3. Ventral view.
Phyllium celebicum "Sulawesi" L3. Ventral view.

Phyllium giganteum "Tapah"

Ventral abdominal ending of female (left) and male (right) nymph in L2.

Phyllium giganteum Tapah L2. Ventral view.
Phyllium giganteum "Tapah" L2. Ventral view.

Ventral abdominal ending of female (left) and male (right) nymph - developing primary sexual characteristics (gonapoyphyses, poculum) are already visible (at least with a good magnifying glass)

Phyllium giganteum Tapah L2. Ventral view.
Phyllium giganteum "Tapah" L2. Ventral view.

Wing buds for female (left) and male (right) nymphs in L2 - the difference in this secondary sexual characteristic is easy to see with a magnifying glass

Phyllium giganteum Tapah L2.
Phyllium giganteum "Tapah" L2.

Female (left) and male (right) nymph in L2. Males have even at this early stage a slightly bell-shaped abdomen. But be cautious, as some female L2 nymphs have quite a similar shape of the abdomen. Therefore this characteristic is to be taken with a grain of salt.

Phyllium giganteum Tapah L2.
Phyllium giganteum "Tapah" L2.

Female (left) and male (right) nymph in L3 - with details of the wings buds. At this stage, males nymphs can easily be distinguised from female nymphs by their already much bigger hind wing buds (which is a secondary sexual characteristic).

Phyllium giganteum Tapah L3.
Phyllium giganteum "Tapah" L3.

Female (left) and male (right) nymph in L4 - with details of the wings buds. At this stage, the hindwing buds of male nymphs are already quite big and easily recognisable. At this stage, nymphs of both sexes are still about the same size.

Phyllium giganteum Tapah L4.
Phyllium giganteum "Tapah" L4.

Female (left) and male (right) nymph in L4 - with details of the primary sexual characteristics (abdominal ending, ventrally). The developing gonapophyses of female nymphs (ventrally on the 8th and 9th abdominal segment) are easily visible with a good magnifying glass. On the other hand, the ventral side of the 9th abdominal segment of male nymphs is fully covered by the developing poculum.

Phyllium giganteum Tapah L4. Ventral view.
Phyllium giganteum "Tapah" L4. Ventral view.

Phyllium letiranti "Tataba"

The differences are easily recognizable in the 3th instar (L3). In L3, the male's abdominal shape is a bit more pointy, and the male's hind wingbuds are much larger

Phyllium letiranti L3.
Phyllium letiranti L3.

Phyllium rubrum "Tapah"

The differences are easily recognizable in the 4th instar (L4). In L4, the male's abdominal shape is a bit more pointy, and the male's hind wingbuds are much larger

Phyllium rubrum Tapah L4.
Phyllium rubrum "Tapah" L4.
Phyllium rubrum Tapah L4.
Phyllium rubrum "Tapah" L4.