Angle shades

Last update: 22 November 2020
SPECIES: Angle shades (Phlogophora meticulosa)
GENUS: PHLOGOPHORA
FAMILY: Owlet moths (NOCTUIDAE)



OBSERVATION:
2021-IV-232021-IV-092020-III-042019-III-242015-XII-162015-XII-132015-XI-292015-XI-282015-XI-192015-XI-152015-XI-082015-XI-042015-X-282015-X-272015-X-22

YEARS:
2015201920202021

MONTHS:
JanFebMarAprMayJunJulAugSepOctNovDec


Agaatvlinder (Phlogophora meticulosa), imago nr 1
Angle shades (Phlogophora meticulosa), imago nr 1
Angle shades (Phlogophora meticulosa)
Angle shades (Phlogophora meticulosa), 5th instar larva

In 2015 I reared four Angle shades moths, see here and here. This species description gives a complete overview of each stage of the development as observed, enriched with information from scientific articles.

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Morphology

Behaviour

Development

 

 

 

 

1. DISTRIBUTION

The Angle shades (Phlogophora meticulosa) is a common moth that can be found throughout the Netherlands [8,9].

2. BEHAVIOUR

2.1. ACTIVITY

The adults are active from March to November [9].

2.2. DEVELOPMENT

The growth phase for the first three instars takes about six days takes between instars, including two days that the caterpillar spends in the ground for molting. The development duration increases for the latter two instars, with the fifth instar taking the longest.

Before pupation the larva needs three days to reach the pre-pupal stage, which will take one day followed by the appearance of the pupa.

Agaatvlinder tijdslijn: instar 1 tot instar 3
Agaatvlinder tijdslijn: instar 4 en 5
Agaatvlinder tijdslijn: prepop tot imago

2.3. FOOD PLANTS

I have observed and raised P. meticulosa on the following food plants:

  frequency garden raised
Lotus berthelotti low x
Nepeta spec. high x x
Mint
(Mentha spec.)
high x x

2.4. OBSERVED BEHAVIOUR

Fouraging

The first and second instar larvae reside at the underside of the leaf they eat from. They remain stationary in one spot and do not relocate. The larva in these stages only feeds on the soft middle parts of the leaf.

The third instar is also mainly located at the underside but is mobile and moves around the plant. It feeds only with lead and eats holes in it.

The fourth and fifth instars consume the leaves whole, including the nerves. These instars roam around the plant and eat a lot very fast.

Poop

The larvae eat a lot and excrete a lot too. The diameter of the turds are somewhat smaller than that of the body and so increase as the larvae grows. Especially the fifth instar produces impressive turds that shrink considerably when they dry out.

Large yellow underwing (Phlogophora meticulosa), 5e instar, poepend
Angle shades (Phlogophora meticulosa), 5th instar, pooping

Consumed food does not remain in the larva for long. I did not measure the duration but after some hours it will be digested and come out.

Before molting a larva will empty it’s bowel, see molting.

Disturbances

When disturbed all instars remain very still.  The first and second instars roll up with the head under the belly. The larger instars are not capable of doing this and just turn the head into the side.

Agaatvlinder (Phlogophora meticulosa), 1e instar, op Munt
Angle shades (Phlogophora meticulosa), 1st instar on Mint
Agaatvlinder (Phlogophora meticulosa), 5e instar, verstoord
Angle shades (Phlogophora meticulosa), 5th instar, disturbed

Molting

All instars hide in the ground to molt. Before it enters the ground it will empty it’s bowel. In case required they will hang around for some time before it is empty.

Pupation can occur in the ground but not necessarily. Two out of three went in to the ground, the third found spot in a folded rearing net.

Agaatvlinder (Phlogophora meticulosa), pop, rups nr 1
Angle shades (Phlogophora meticulosa), puppa, caterpillar nr 1

The depth the larvae dug to differed per larva. One of the larvae spun its cocoon just below the surface underneath the earth, making use of leaves.

Agaatvlinder (Phlogophora meticulosa), pop in aarde
Angle shades (Phlogophora meticulosa), pupa in earth

The other was a few cm deep without a cocoon. As an experiment I put the larva in a box with dried leaves but it did not spin a cocoon and pupated on the plastic.

Agaatvlinder (Phlogophora meticulosa), pre-pop, rups nr 3
Angle shades (Phlogophora meticulosa), pre-pupa, caterpillar nr 3

Cremaster use

The cremaster at the tip of the abdomen of the pupa is fork shaped. The larva will twist it’s abdomen so the cremaster will twist around too. The cremaster will hook on the surface or items in the direct environment which makes the pupa rapidly turn over an angle. The pupa is capable of repositioning itself like this. I don’t think it has a defensive function as the pupa is too limited in movement and reach. Possibly it is a deterrent. As the pupa ages this behaviour becomes less powerful, possibly because the pupa hardens and looses flexibility to twist.

Agaatvlinder (Phlogophora meticulosa), pop met cremaster
Angle shades (Phlogophora meticulosa), pupa with cremaster

Food

The adults are rather easy to feed in captivity using sugar water or a spread on branches, for example butterfly syrup using one the recipes published by the ‘Vlinderstichting’ (Butterfly foundation), see here.

Angle shades (Phlogophora meticulosa)
Angle shades (Phlogophora meticulosa)

2.5. IDENTIFICATION

EGGS

The P. meticulosa eggs are white colored and shaped like an upside down hemisphere covered with ribs in length and width.

Angle shades (Phlogophora meticulosa), egg

INSTARS

P. meticulosae has 5 instars, ie. four molts, before the prepupal and pupal phase.

Agaatvlinder (Phlogophora meticulosa), metamorfose
Angle shades (Phlogophora meticulosa), metamorphoses

 

(mm) instar 1 instar 2 instar 3 instar 4 instar 5
Length ±0,3 – 0,5 ±0,6 – 0,8 ±0,9 (?) – 15 ±15 – 25 ±28 – 45
Head width ±0,2 0,5* (?) ±1 ±1,8 ±3,6
Color yellow-green yellow-green yellow-grassgreen grassgreen brown
(or green)
Prolegs 3 pairs 3 pairs 5 pairs 5 pairs 5 pairs

*the head of the second instar is not measured but determined using Dyar’s law [3]. Calculation of the headshields shows a growth ratio of ±2.

Color

During rearing I’ve observed the following color variations:

  • The first and second instars are yellow-green and glass-like. Starting from the first instar the back is darker than the belly.
  • The third instar is greener than the first and second instars.
  • The fourth instar is greener than the third.
  • The fifth instar is brown.

The larvae have a large variety in colors that have been extensively descried by Majerus. The final fifth instar has two appearances:

  • green
  • brown

The definitive color appears in the fifth or just before moulting in the fourth instar. After molting the larva is first pale yellow-brown and turns slowly darker in color.

Agaatvlinder (Phlogophora meticulosa), 5e instar, bleke geelbruine kleur na vervelling
Angle shades (Phlogophora meticulosa), 5th instar, pale yellow-brown color after molting
Angle shades (Phlogophora meticulosa), 5th instar larva on Dame’s rocket (Hesperis matronalis)

All larvae I reared were of the brown variant. One specimen changed color in the fourth instar, from green to brown, however it died prematurely.
In two other larvae I did not observe the color change.
With one larva I’m sure it did not change color as it was green a day before molting.

Majerus [4] has investigated and described the color change of the species thoroughly, including the color change observed by me.
Color changes can occur between second to third, and third to fourth instars as well. So the color change in the specimen that died seems unrelated to the cause of death.

Majerus has established that the larvae occur in six different colors [5].

  1. Green
  2. Olive green
  3. Brown
  4. Yellow
  5. Yellow green
  6. Yellow brown

A specific colorcode is assigned to the first and second (EG = early green), and the third instar (3IG = 3e instar green).

Color changes can occur twice during growth and may occur in different directions, with some of those directions excluded:

  • change from olive green or brown to green has not been observed
  • change from from brown to olive green has not been observed
  • change from olive green to green has only been observed during second and third molt
  • change from green to brown has only been observed during the second, third or fourth molt
  • change from olive green to brown has only been observed during the fourth molt

Majerus reports a special group with a green-pink color. This group has a disproportionate high mortality rate and also the adults that appeared from them were deformed.

Majerus established that food is the only external influence [5] on the color of the larvae (temperature, light, groups, environment color are excluded from being influential factors). The effect of food on the larval color is not uniform across instars:

  • food is the determining factor in first and second instars
  • in the third instar food (highest percentage) or genes determine it
  • the fourth and fifth instars are influenced only by genes, food does not play a role

Optically however food can play a role as is seen in the photograph. The green color is a result of leafmass in the larval’s digestive system.

Agaatvlinder (Phlogophora meticulosa), 5e instar, groene kleur door plantenmateriaal in spijsverteringsorgaan
Angle shades (Phlogophora meticulosa), 5th instar, green color as result of plant material in the digestive system (head left)

Another fluctuating color characteristic is the head color. In the first and second instars the ground color is light brown, in the third and fourth light green-beige and in the fifth instar light cream with brown spots. In every instar the head color gets darker because the ground color becomes browner and spots appear on it. Majerus does not mention this in his reports.

Markings

From the marking there are three aspects that change between instars:

  1. Stripe one the sides
  2. Light dots on the body
  3. Dark stripes on the back

The first instar has a glass-like green color and no other markings.

As of the second instar a milky-white stripe develops across the stigma on the side of the body. After molting this stripe is still vague but will become clearer as the larva grows. When the larva has a brown ground color the stripe is more pinkish in color.

Large yellow underwing (Phlogophora meticulosa), lateral line
Agaatvlinder (Phlogophora meticulosa), laterale lijn (kop links)

From the third instar on small white dots appear over the entire larval body, which are dorsally aligned into a line pattern. In the dorsal centre they are clearest, and in the fifth instar these are the only visible stripes.

From the fourth instar characteristic V-shaped angled lines appear dorsally, which points to this species.

Agaatvlinder (Phlogophora meticulosa), dorsale lijn
Angle shades (Phlogophora meticulosa), dorsal line (head left)

Prolegs

Remarkably the first and second instar larvae have proleg configuration like a looper [1], with three sets of prolegs on segments A5, A6 and A10. However after the second molt the third instar will have five legs that it will use.

Agaatvlinder 1e en 2e instar propoot configuratie is een spanrups configuratie
Angle shades 1st and 2nd instar proleg configuration is like a looper

On this photo the looper behaviour can be seen.

Agaatvlinder (Phlogophora meticulosa), 1e instar
Angle shades (Phlogophora meticulosa), 1e instar

The first as well as the second instar has clear proleg protrusions on the abdominal segments A3 and A4 that look like they are underdeveloped compared to the other prolegs. The prolegs do bear crochets [2] already.

Angle shades (Phlogophora meticulosa), 1st instar, prolegs and crochets
Angle shades (Phlogophora meticulosa), 1e instar, propoten en crochets (kop rechts)
Large yellow underwing (Phlogophora meticulosa), 2nd instar, prolegs and crochets
Angle shades (Phlogophora meticulosa), 2e instar, propoten en crochets (kop links)

The third instar has well developed prolegs on segments A3 en A4 and the ‘standard’  caterpillar configuration with five prolegs.

Propoten rups
Mixmal number of prolegs on the fourth and fifth instars
Agaatvlinder (Phlogophora meticulosa), 3e instar
Angle shades (Phlogophora meticulosa), 3e instar

Crochets

P. meticulosa crochets are shaped uniordinal and penelliptic [6]. This means they are aligned in one row (uniordinal) and shaped like an open ellipse (penelliptic).

Crochets in uniordinale penelliptische opstelling
Crochets in uniordinale penelliptische opstelling
Agaatvlinder (Phlogophora meticulosa), 5e instar, crochets (kop rechts)
Angle shades (Phlogophora meticulosa), 5th instar, crochets (head left)
Agaatvlinder (Phlogophora meticulosa), 4e instar, crochets (kop links)
Angle shades (Phlogophora meticulosa), 4th instar, crochets (head left)
Agaatvlinder (Phlogophora meticulosa), 4e instar, crochets (kop rechts)
Angle shades (Phlogophora meticulosa), 4th instar, crochets (head left)

The later instars (at least the fourth and fifth) have difficulties keeping hold on smooth surfaces (also compared to similar large larvae of the Pieris brassicae and other large larva).

The first instar has no problem with the same surface. This may be related to the weight of the larva, but possibly the shape of the crochets plays a role as well as they have a different configuration, i.e. uniordinal on a straight line across the foot.

Crochets in uniordinale opstelling
Crochets in uniordinale opstelling
Agaatvlinder (Phlogophora meticulosa), 1e instar, crochets (kop links)
Angle shades (Phlogophora meticulosa), 1st instar, crochets (head left)

Setae

The first and second instars have a clear pattern of black dots, warts, on every segment of the thorax and abdomen. In every wart grows a black hair or seta.
The warts disappear after the second molt and are replaced by lighter spots with a black ring in it that contains the seta. The spot color takes the gorund color, pale green if the ground color is green or cream colored on a brown ground color. The setae themselves become lighter after every molt.

Agaatvlinder (Phlogophora meticulosa), setae ontwikkeling
Angle shades (Phlogophora meticulosa), setae development

Analshield

The analshield of the first and second instars is clearly differently colored than the rest of the body. From the third instar onwards the shield takes the color of the body’s ground color. Up to the third instar the shield is shaped as a clear bulge on the last abdominal segment. From the fourth instar it is less pronounced.

Angle shades (Phlogophora meticulosa), anaalschild
Angle shades(Phlogophora meticulosa), analshield

Neckshield

All instars have a neckshield, but from the 3rd instar on it is no longer a well developed plate but more an area with a different drawing. The shield always bears a double row of setae, one at the front edge and one at the apical edge.

Angle shades (Phlogophora meticulosa), nekschild
Angle shades (Phlogophora meticulosa), neckschields

Neck spots

Some time after molting the caterpillar larval side bears a characteristic area that look like a half ring of stemmata. This is only visible after molting when the skin is still tight. After some time the larve grows fatter and the spot is hidden behind a fold over the head, I havent been able to directly observe this.
Every instar has this characteristic with exception of the first instar, what could be as a result of the fact that I only spotted the first instars some time after they had hatched and the area had already been covered.

Angle shades (Phlogophora meticulosa), nek vlekken
Angle shades (Phlogophora meticulosa), neck spots

Cremaster

The pupal cremaster, a protrusion on the tip of the abdomen, is shaped like a fork with two teeth. The pupa shows remarkable behaviour in the use of this instrument, see the description in the paragraph behaviour earlier in this article.

Angle shades (Phlogophora meticulosa), pop met cremaster
Angle shades (Phlogophora meticulosa), pupa with cremaster

Adults

Angle shades (Phlogophora meticulosa), imago nr 3
Angle shades (Phlogophora meticulosa), imago nr 3
Angle shades (Phlogophora meticulosa)
Angle shades (Phlogophora meticulosa)

4. PARASITAIRE RELATIES

P. meticulosa wordt geparasiteerd door de volgende soorten in de tuin:

Wespen (HYMENOPTERA)


References

1 Kerfdier, 2015, Vergelijking rups en spanrups

2 Kerfdier, 2015, Vergelijking rups en bastaardrups: crochets

3 Dyar, H.G., 1890, "The Number of Molts in Lepidopterous Larvae"

4 Majerus, M.E.N., 1983, "Larval Colour Variation in Phlogophora Meticulosa (L.). Part II: Genetic Control in Instars 3-5", page 66

5 Majerus, M.E.N., 1983, "Larval Colour Variation in Phlogophora Meticulosa (L.). Part I: Genetic Control in Instars 1-3", page 46, 41

6 Treadwell, L., 1996, "An Itroduction to the Identification of Caterpillars"

7 HINZ, Rolf; HORSTMANN, Klaus. Über Wirtsbeziehungen europäischer Ichneumon-Arten.

8 Vlinderstichting en Werkgroep Vlinderfaunistiek (WVF) van EIS-Nederland, Voorlopige Rode Lijst Macronachtvlinders

9 Waarneming.nl

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