Imperial Hairstreak (Jalmenus evagoras)

Imperial Hairstreak (Common Imperial Blue) Jalmenus evagoras
Wingspan: 32 - 37mm

Sighted Claire Cottage: October to May

Distribution: Central QLD, NSW, ACT to Central VIC

Status Claire Cottage: Very common
Status Dorrigo Plateau: common

Imperial Hairstreak

Mating Imperial Hairstreaks

Our regeneration paddock is perfect habitat for the Imperial Hairstreak butterflies where some of the trees are still quite small. It seems they prefer to lay their eggs in batches on young wattle trees up to about two metres high.

Early one evening Trev saw twenty-four newly hatched butterflies grouped together roosting on a small acacia tree.

These butterflies generally fly around the paddock area, occasionally visiting nectar flowers in the garden.

Common Imperial Blue on yellow daisy

Jan 2018, 8.30 am

Claire Cottage Dorrigo Plateau, Jan 2019, 2.34 pm

This female was searching for a suitable crevice to lay eggs. Claire Cottage Dorrigo, Jan 2019, 2.55 pm

She walked over all the branches and up and down the trunk with abdomen lowered. We watched for 20 mins. She was still searching when we left.

In January 2016 we watched a female laying eggs in a crevice of an Acacia branch (see pictures below). We were interested to note that there were no ants on the tree at that time. The following day a few ants were moving about the tree. None were showing interest in the batch of eggs.

Female laying eggs an 24/01/16 in Acacia branch crevice - no ants present on tree

Cluster of eggs laid on 24/01/16 in Acacia branch crevice - difficult to see with naked eye

Eggs on 24/01/16 greatly magnified showing their amazing shape - not visible with the naked eye

Same eggs on 12/02/16 - many appear to have openings - if they have hatched there are no larvae visible. Has a predator attacked the eggs? Ants are present on the tree but not attending the eggs.

Larva with attendant ants

A larvae with this many ants is easy to see

The caterpillars are attended by black ants that protect them from birds and parasitic wasps. In return the ants 'milk' the caterpillars for a honey dew like substance. They often appear as black lumps in the trees as the ants can completely cover the caterpillars and pupae as in the pictures below.

A cluster of larvae

Cluster of larvae and resultant bare branches, Claire Cottage Dorrigo Plateau, 31 Jan 2018

Eggs laid on a branch rather than in a crevice of a sapling, Claire Cottage Dorrigo, 22 Jan 2020

Pupae with attendant ants

Eggs laid in a sapling in photo below left, Claire Cottage Dorrigo, 22 Jan 2020

Another batch of eggs, Claire Cottage Dorrigo, 22 Jan 2020

Males clustering near pupae waiting for females to hatch Claire Cottage Dorrigo NSW, 11 Feb 2021

Some of the pupae in foreground with attendant ants, Claire Cottage Dorrigo NSW, 11 Feb 2021

Oct 2005, 2007, 2008, 2009, 2013,
Nov 2004, 2005, 2006, 2007, 2008, 2009, 2011, 2013, 2014, 2015, 2016, 2018, 2019, 2020,
Dec 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2012, 2014, 2015, 2018, 2019, 2020,
Jan 2002, 2005, 2007, 2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018, 2019, 2020, 2021,
Feb 2006, 2007, 2008, 2009, 2010, 2011, 2014, 2015, 2016, 2017, 2019, 2020, 2021,
Mar 2004, 2007, 2008, 2009, 2010, 2011, 2013, 2014, 2015, 2016, 2017, 2018, 2019, 2020,
Apr 2004, 2007, 2008, 2009, 2010, 2011, 2013, 2015, 2016, 2018, 2020,
May 2007, 2009, 2011, 2013, 2016

DORRIGO PLATEAU elsewhere: Dorrigo in 1990's.

Larval Sightings:

CLAIRE COTTAGE: In good numbers every warm season from 2002 to 2021
DORRIGO PLATEAU elsewhere: None to date

Larval Food Plants:

CLAIRE COTTAGE: FABACEAE: Acacia melanoxylon
DORRIGO PLATEAU elsewhere: (as for Claire Cottage)

ELSEWHERE: FABACEAE: as for Claire Cottage & many other species of young Acacia

Habitat where found at Claire Cottage: self seeding juvenile Acacia trees to about 3 metres high

Flight habit: Throughout the day usually homing in on one tree with larva and ants already established. Periodically adults will sit in the tree near where pupa are being protected by hordes of ants.

First sighting summer 2004 of an adult - November 6th
First sighting summer 2006 of an adult - November 12th
First sighting summer 2007 of an adult - October 27th (male)
First sighting summer 2008 of an adult - October 31st
First sighting summer 2009 of an adult - October 22nd
First sighting summer 2010 of an adult - December 8th (very wet Spring)
First sighting summer 2011 of an adult - November 25th
First sighting summer 2013 of an adult - October 29th
First sighting summer 2015 of an adult - November 12th
First sighting summer 2016 of an adult - November 13th
First sighting summer 2018 of an adult - November 18th - First sighting summer 2018 of larva - November 5th
First sighting summer 2019 of an adult - November 13th - First sighting summer 2019 of larva - November 13th

Last sighting autumn 2007 of an adult - 11/04/07 - Last sighting autumn 2007 of larva -
Last sighting autumn 2009 of an adult - 07/05/09 - Last sighting autumn 2009 of larva -
Last sighting autumn 2011 of an adult - 05/05/11 - Last sighting autumn 2011 of larva -
Last sighting autumn 2013 of an adult - 05/05/13 - Last sighting autumn 2013 of larva -
Last sighting autumn 2016 of an adult - 05/05/16 - Last sighting autumn 2016 of larva -                                     -
Last sighting autumn 2018 of an adult - 10/04/18 - Last sighting autumn 2018 of larva -                                     -
Last sighting autumn 2019 of an adult - 11/05/19 - Last sighting autumn 2019 of larva -                                     -
Last sighting autumn 2020 of an adult - 30/04/20 - Last sighting autumn 2020 of larva -
Last sighting autumn 2021 of an adult - 00/00/21 - Last sighting autumn 2021 of larva -                                       -