Early Stage of the Forget-Me-Not (Catochrysops strabo)

 Early Stage of the Forget-Me-Not (Catochrysops strabo)

Butterfly description:

The Forget-Me-Not butterfly is uncommon in both Malaysia and Singapore, but it can be frequently found in shrublands, open fields, and forest edges. In Singapore, the butterfly often flies alongside its close relative, the Silver Forget-me-Not (Catochrysops panormus), as well as the Gram Blue (Euchrysops cnejus), as these three species share some of their host plants.

Key to Identification:

Forget-me-not (C. strabo)
- Underside forewing with a spot on the costa midway between the spot at the end of the cell and post discal band
- male upperside purplish blue in color
- female UPHW spaces 7 & 8 are brown color

The Silver Forget-me-not (C. panormus)
- Underside forewing with the costal spot adjoining the upper end of the post-discal band.
- male upperside sky blue in color
- female UPHW spaces 7 & 8 are same color as the space below it

Host plant:
Desmodium heterocarpon

The host plant found in an open field or land being developed in Singapore.

Host plant: Desmodium heterocarpon, flower (left), seedpods (right).

Habitat of the Forget-me-not and the host plant

Early stage description:

The early stage of the Forget-me-not feeds on the flower buds, flowers, and young seedpods of the host plant, while mature caterpillars tend to feed on the seedpods when available. The Silver Forget-me-not also utilizes the same host plant (Desmodium heterocarpon).

Life cycle
Egg: 2 - 3 days
Larva: 17 - 18 days
Pupa: 6 - 7 days

A Forget-me-not female laying egg on Desmodium heterocarpon

Eggs are laid singly between the flower buds of the host plant. The egg is rounded in shape, with some having large depressions or dents on the surface (left photo). Some eggs are covered with a semi-transparent substance on one side (right photo), possibly acting as a glue to hold the egg onto the host plant.
 

Egg with dents on the surface (left), with semi-transparent substance (right)

It takes about two to three days for the egg to hatch. The larva is yellowish-brown in color and has long setae on its body. It takes about 17-18 days for the larva to form a pupa.

Day 1 (hatched from egg) - Two views of a 1st instar caterpillar

Day 2

Day 3

Day 4

Day 5

Day 6

Day 7

Day 8

Day 9

Day 11

Day 14

Day 15 - 

Day 16 - Two views of a pre-pupa of the Forget-me-not, green form

Two views of a pre-pupa of the Forget-me-not, red form

2nd days in the pre-pupatory stage

Roughly 6-7 days later, the pupa darkens in color, indicating that the adult butterfly is about to emerge. The following day, the adult Forget-me-not butterfly emerges from the mature pupa.

Two view of a pupa of the Forget-me-not

A mating pair of the Forget-me-not

Reference:

• Life Cycle of A Forget-me-not by Ben Jin Tan (9 Feb 23)
• The Butterflies of The Malay Peninsula, A.S. Corbet and H.M. Pendlebury, G. and N.  van der Poorten (Eds.), 5th Edition, Malayan Nature Society, 2020.
• Butterflies of Thailand, Pisuth Ek-Amnuay, 2nd Edition, 2012.