Sapphire Flower Beetle Care Guide: Protaetia speciosa cyanochlora (UK)

The Sapphire Flower Beetle is a Persian chafer the size of a two-pence piece, dark metallic blue from head to tail, that spends most of its life as a fat white grub in a bed of rotted leaves and wood before emerging to feed on fruit in full sun. Protaetia speciosa cyanochlora comes from the Zagros mountains of western Iran, wants ordinary room temperature rather than a warm cupboard, and takes about a year from egg to adult in most keepers' hands. The one thing that divides the breeders is whether it needs a cool winter rest to stay fertile, and this guide gives you both sides of that argument.

What You Are Actually Keeping

The trade and the catalogues spell the name differently. The catalogues carry Schauer's 1941 name as cyanichlora, with an i: Protaetia speciosa cyanichlora is the Catalogue of Life spelling. The hobby, most sellers and Wikipedia write cyanochlora, so that is the spelling in our title; the catalogue spelling is given here once so nobody thinks they are two beetles. It is also sold as the Sapphire of Persia. It is a subspecies of Protaetia speciosa, a species running from the Crimea and the Caucasus through Turkey and the Near East into Iran. It is not the big green European chafer that older books call Protaetia aeruginosa: that animal is now Protaetia speciosissima, a separate species in the same subgenus. Nothing protects the Iranian beetle under British law, and the stock in the hobby is captive-bred.

Published ranges are 20 to 32mm for the species, from Pierre Tauzin's Cetoniinae pages, and 24 to 30mm for the nominate form, from the Red Data Book of Ukraine; nobody has published one for the blue subspecies, and sellers quote 25 to 30mm. The colour is a uniform dark blue with a metallic shine above and below, though green individuals turn up in captive lines and one beetle can read blue or green as the light moves. In the wild the larvae live in the rotten wood of hollows and stumps in old broadleaved trees, and the adults fly by day in bright sun and feed on sap, ripe fruit and the odd flower.

The Cycle, and the Argument About Winter

Three larval stages, a cocoon, a pupa, then the adult. The Ukrainian Red Book gives a wild generation as one to two years. In captivity the European breeders who publish figures say eleven to thirteen months from egg to beetle, or about a year with a cold rest built in; two Japanese keepers who ran their larvae warm all year, one at 25 to 27°C and one at 20 to 22°C with a warmer summer, took them from first-stage grub to adult in about seven months.

Most of the breeders who publish figures for it say it needs a winter rest: two to three months at roughly 5 to 10°C, given either to the fat late-stage grubs or to freshly emerged adults, with the temperature brought down over two or three weeks rather than in a day. Their reason is fertility, and one Cornish breeder puts it as strongly as "must have". Against that, the two Japanese accounts bred and reared through warm, one female laying 57 eggs in three weeks with no cold at all. There is no published test on this species. The closest thing in print is a Korean study on the related Protaetia brevitarsis, in which indoor-reared beetles laid normally in the first generation and nothing in the second, while pupae chilled at 5°C for a month, after acclimation, gave the females that laid most. A different species, but the same shape of result the European breeders describe, and it is why we lean their way.

Our own larvae are the first generation here, so the second-generation question is one we will answer in our own tubs. Until we have, the plan is to give the rest: an unheated room or garage that sits at 6 to 10°C through the coldest months, for the fresh adults this winter before they are paired. If you would rather run warm and fast, the Japanese results say you can get a generation that way; what nobody can promise you is the generation after it.

The Grub Bed

The larvae eat the bed they live in, so the bed is the whole diet. What suits a chafer grub is flake soil as the base, a generous share of well-rotted hardwood leaves worked in, and pieces of rotten wood soft enough to crumble in the hand. Breeders argue about the proportions, from four parts leaf to one part wood at one end to an almost pure fermented mat at the other, and the grubs grow on all of them. No softwood of any kind, and no coir: coir is not food, and a grub in it will not grow.

Kinshi, the fungus-run hardwood that stag beetle keepers rear in, is not the medium for a flower beetle grub; our kinshi article covers what it is, and a handful of the dried form crumbled through a leaf-and-wood bed is harmless enrichment. Added protein is a different matter. Two European sellers add it from the second instar, but a controlled trial on a wood-feeding flower beetle found extra protein made no difference to growth, and a protein pellet buried in a damp bed is the surest way we know to start a mite bloom, so we bury none.

Depth of 10 to 15cm at least. Moisture is the hand test: the bed should clump and hold its shape when squeezed and never drip. It is a mountain insect from a country with cold winters, does well at ordinary room temperature, which the sellers put anywhere between 20 and 28°C, tolerates a good deal cooler with development slowing, and flower beetle grubs in general are reported to die if held above 30°C for long, so there is no case for heat kit on a grub tub at all. The grubs are not cannibals and are normally reared together, at something like one large grub per half-litre to litre of bed; a few keepers rear singly in pots, which costs more changes.

Air a new bag of substrate for a day or two before it goes in, because a bed that is still fermenting smells sour and can warm itself, and freeze every new batch for 48 hours first. That last step is about mites. Flake soil is close to an ideal diet for the grain and mould mites of every invertebrate room, a bloom in a larval tub usually arrives with the substrate, and you cannot dry a grub bed out to clear one without harming the grubs. Our article on grain mites has a section written for beetle grubs, including the published case it rests on, a four-millimetre tobacco beetle grub and not a chafer. Nobody has tested a flower beetle larva, and we will not pretend that result carries across; it is simply the reason to be tidier with a grub tub than with an isopod one.

The Cocoon

A big third-stage grub that is ready to pupate stops feeding, turns yellowish and presses the finer material of the bed into an oval cell around itself, often against the wall or floor of the tub. From the moment a cell appears, leave it alone: a grub disturbed while building will wander as a grub and usually dies, and a cell opened to look inside rarely closes again. Let the bed dry a little, not out, through this stage, because several breeders link a wet cocoon to deformed wing cases and to mites.

Japanese keepers reckon a flower beetle spends two to four weeks in the cell as a pre-pupa, about a month as a pupa and two or three weeks colouring up before it breaks out: call it two months from a finished cell to a beetle on the surface. In the wild the sister species finishes its change in autumn, sits out the winter inside the cell as a fully formed adult and comes up in spring; a fresh beetle can take a while to settle, with one keeper reporting about three months from emergence to breeding condition. Do not force a fresh adult to feed until it wants to.

The Adults

In the wild it flies on bright, clear days, and breeders agree it should have a bright lamp over the enclosure by day. Whether they strictly need it has never been tested, and one German site says an ordinary bulb does the job and reptile UV is unnecessary; the plan here is a lamp on a twelve-hour timer.

Give a group a tub of 30cm a side or more, with 10 to 15cm of the same bed underneath and the bottom third pressed down firm, because that packed layer is where the females lay. Cork and a few flat stones on the surface give the beetles something to climb. Food is ripe fruit, banana above all, and beetle jelly, which stays clean for days; a pinch of bee pollen is taken too, and fruit comes out before it sours. Temperature 20 to 28°C for active, laying adults, with the mid-twenties ideal; the beetles sit through cooler spells without harm. Humidity is the least agreed figure of all: sellers give 60 to 80 and 70 to 90 per cent, our fruit beetle guide runs 50 to 70, and the sensible reading is a damp bed under a drier surface and enough ventilation that the lid never fogs.

Then the lid. Flower chafers fly with the wing cases closed, through a notch at the shoulder, so they are quick off the mark. The lid is close-fitting mesh and it is on whenever your hands are not in the tub. Adults live several months: six months is the figure sellers give for the group, one breeder kept a pair together for just over eleven, and the sister species is reported to two years.

Breeding

Given the bed, the lamp and the fruit, a pair or a small group breeds without much help. One Japanese keeper counted 57 eggs and young larvae from a single female in three weeks at 25 to 27°C, a Cornish breeder had eighteen larvae from a first pair and 78 from a 2025 pair, and a French seller rates the closely related Near Eastern subspecies as average to low in prolificacy. Eggs hatch in two to five weeks depending on warmth. Adults dig, and can dig up their own eggs; the packed layer is the usual answer, and moving the adults to a fresh box every couple of months is the belt-and-braces one. Wait a month after the last adult has gone before you sift for larvae, and sift by hand rather than with a tool.

Nobody has published inbreeding depression in any flower beetle, so we will not claim it; outbred stock is the prudent way to start a colony you mean to keep for years, and swapping a few animals with another keeper every generation or two costs nothing.

Telling Males from Females

With difficulty, and we will not print a character we cannot stand behind. The groove down the underside of the abdomen that separates male from female in the rose chafer Cetonia aurata is quoted for every flower beetle, but the German literature says both sexes of the closely related Protaetia cuprea lack it, and no published description gives a sexing character for this species. One Belgian breeder of the European sister species sexes adults by the length of the hind tarsus, about equal to the tibia in males and shorter in females, and by the shape of the last belly segment, flat and smooth in the middle on a male. We will check both on our own adults when they emerge and put what we find here. Until then, a group of five or six is the reliable way to be sure of both sexes.

The Law

As far as we can find, no licence is needed to keep this beetle in Britain: it is not on Schedule 9 of the Wildlife and Countryside Act 1981, and it is not a CITES species. It is not native either, and that is the part that matters. Section 14 of the same Act makes it an offence to release, or to allow to escape into the wild, any animal of a kind not ordinarily resident in Great Britain in a wild state, and in Scotland the wording is any animal outwith its native range. The words to notice are "allow to escape": intent is not the test, and the defence in England and Wales is that you took all reasonable steps, which an open window is not. Keep the lid on, pass surplus larvae to other keepers, and never put substrate that might hold eggs out on a compost heap.

Ours

I have a group of larvae growing on now, and they should cocoon and emerge over the next couple of months. I also have larvae of Protaetia elegans, the Taiwanese species, and will confirm the identity once the adults are out. Offspring go on sale once I have a colony breeding here rather than a first clutch, which is how every animal on this site earns its listing. The rest of the beetles we keep are on the beetles for sale page, and the African fruit beetle guide covers the warm-country cousin of this one.

Frequently Asked Questions

Is Protaetia speciosa cyanochlora a good first beetle?

It is easy to rear from a grub and undemanding at room temperature. A German seller calls it suitable for beginners; a French seller marks the Near Eastern subspecies as not, and the winter rest and modest egg count are the likely reasons. A fruit beetle gives a first-time keeper faster results with fewer decisions.

How long does it take from egg to beetle?

About a year at room temperature with a winter rest, seven to eight months if held warm all year, and about two months from a finished cocoon to a beetle on the surface.

Does it need a heat mat?

No. Room temperature suits the grubs, a bright lamp warms and lights the adults by day, and sustained heat above 30°C is reported to kill flower beetle larvae.

Why is my grub on its back?

Because that is how flower beetle grubs move. They travel upside down on the bristles of the abdomen, and a grub crossing the surface on its back is behaving normally.

Can it live with my fruit beetles?

Not in a breeding box. This one probably wants a cold winter that a fruit beetle must not have, the grubs compete for the same bed, and you will not be able to tell whose eggs are whose. Separate tubs, same substrate.