Mae’r oedolion yn hedfan yn agos i’r ddaear, gan aros yn aml i gymryd neithdar o flodau megis Mieri ac Ysgall. Gellir gwahaniaethu rhyngddi a’r Fritheg Berlog ar sail y perlau gwynnaidd mwy niferus sydd ar du isaf yr adennydd cefn, y sieffrynau duon sydd o gwmpas y perlau allanol, a’r smotyn canolig du sy’n fwy o faint.
Erys y glöyn byw yma’n eang ei ddosbarthiad ac yn niferus mewn mannau yn yr Alban a Chymru, ond mae ei niferoedd wedi gostwng yn arw yn Lloegr.
Gwelir y glöyn byw mawr grymus hwn fel rheol yn hedfan yn chwim uwchben y rhedyn neu’r tyfiant isel mewn llennyrch yn y coed. Tra’u bod yn hedfan mae hi bron yn amhosibl gwahaniaethu rhwng gwrywod y rhywogaeth hon a rhai’r Fritheg Werdd, sydd yn aml yn cydrannu’r un cynefinoedd. Ond mae’r ddwy rywogaeth yn ymweld yn aml â blodau megis Ysgall a Mieri, lle mae’n bosibl gweld y marciau gwahaniaethol ar du isaf yr adennydd. Nid oes gan y Fritheg Werdd y ‘perlau’ â chylch lliw oren o’u cwmpas sydd ar du isaf adenydd cefn y Fritheg Frown.
Mae’n hawdd peidio â gweld ein glöyn byw brodorol lleiaf i gyd, yn rhannol oherwydd ei faint a’i liw tywyll, ond yn rhannol hefyd oherwydd na ddeuwn o hyd iddo’n aml ond ar glytiau bach o laswelltir cysgodol lle mae ei unig blanhigyn bwyd, sef Meillion Melyn (Bysedd Mair), i’w weld yn tyfu.
Until recently this was only a rare immigrant to mainland Britain, but it is now resident in small numbers in Devon. It also appears occasionally elsewhere on the south-west coast and is resident in the Channel Islands.
Flight Times
Flies in July and August, and then in September and October. The second brood overwinters as an adult and reappears in the spring.
Size and Family
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Family – Erebidae
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Small Sized
The females of the Pale Brindled Beauty are completely wingless, or apterous, a feature which is often found in moths which emerge in the winter months.
This species shows marked melanism, the black form f. monacharia being commoner than the typical form in certain parts.
Flight Times
Males fly from January to March, searching for the females which have climbed up tree-trunks.
Size and Family
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Family – Geometridae
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Medium Sized
A species of autumn and spring, the Red-green Carpet can be seen in September and October before hibernating as an adult and flying again in the early spring.
The adult moth has a subtle combination of reddish and green colours which can sometimes appear to change, depending on the light.
Flight Times
Flies in September and October, hibernating as an adult and flying again in early spring.
Size and Family
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Family – Geometridae
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Small/Medium Sized
A migrant species that can sometimes arrive in large influxes with other migrants.
The Rusty Dot Pearl has multiple generations each year, usually spending winter as a pupa in the soil.
Caterpillars can reach a length of 10–15 millimetres (0.39–0.59 in. The adult moth flies at night and is attracted to light.
Flight Times
Primarily a migrant species to the UK but can be found at almost any time of the year.
Size and Family
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Family – Crambidae
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Small Sized
A variable species, with some strongly-banded individuals, others plain brownish with darker speckling. The females are completely wingless. Overwinter as an egg.
Flight Season
Flies from October into December in one generation.
The name 'Wax Moth' refers to the moth's lifestyle - it lives in beehives, where the larvae feed on the honeycomb. Adults can be attracted to light.
The males of this species have a distinctively concave outer edge to the forewing; the females are generally plainer in appearance with a less concave edge.
Flight Season
Flies between June and October.
Similar to other species and can be very difficult to separate on markings alone, especially as some show marked melanism.
Caterpillars can be found in late spring.
Flight Season
Flies from late September to November in one generation.
Size and Family
- Family – Geometridae
- Medium Sized
- Wingspan Range – 38-44mm
Conservation status
- UK BAP: Not listed
- Common
Caterpillar Food Plants
Caterpillars feed on a variety of trees and shrubs.