It is hardly feasible to decide positively by the methods which I have been following whether the honey is or is not repugnant to the grubs of the Philanthus. The first mouthfuls consist of meat; and then nothing particular occurs: it is the natural diet. The honey is met with later, when the morsel has been largely bitten into. If hesitation and lack of appetite are displayed at this stage, they come too late in the day to be conclusive: the larva's discomfort may be due to other, known or unknown, causes. The thing to do would be to offer the grub honey from the first, before artificial rearing has affected its appetite. It is useless, of course, to make the attempt with pure honey: no carnivorous creature would touch it, though it were starving. The jam-sandwich is the only device favourable to my plans, a meagre jam-sandwich, that is to say, the dead Bee lightly smeared or varnished with honey by means of a camel's-hair pencil.
Under these conditions, the problem is solved with the first few mouthfuls.
The grub that has bitten into the honeyed prey draws back in disgust, hesitates a long time and then, urged by hunger, begins again, tries this side and that and ends by refusing to touch the dish. For a few days it pines away on top of its almost intact provisions; then it dies. All that are subjected to this regimen succumb. Do they merely perish of inanition in the presence of an unaccustomed food, which revolts their appetite, or are they poisoned by the small quantity of honey absorbed with the early mouthfuls? I cannot tell. The fact remains that, whether poisonous or repugnant, the Bee in the state of bread and jam is death to them; and this result explains, more clearly than the unfavourable circumstance of my former experiment, my failures with the Bee that had not been made to disgorge.
This refusal to touch the unwholesome or distasteful honey is connected with principles of nutrition which are too general to constitute a gastronomic peculiarity of the Philanthus. The other carnivorous larvae, at least in the order of the Hymenoptera, are bound to share it. Let us try.
We will go to work as before. I unearth the larvae when they have attained a medium size, to avoid the weakness of infancy; I take away the natural provisions, smear the carcases separately with honey and, when this is done, restore its victuals to each of the grubs. I had to make a choice:
not every subject was equally suited to my experiments. I must reject the larvae which are fed on one fat joint, such as those of the Scolia. The grub in fact attacks its prey at a determined point, dips its head and neck into the insect's body, rooting skilfully in the entrails to keep the game fresh until the end of the meal, and does not withdraw from the breach until the whole skin is emptied of its contents.
To make it let go with the object of coating the inside of the venison with honey had two drawbacks: I should be compromising the lingering vitality which saves the insect that is being devoured from going bad and, at the same time, I should be disturbing the delicate art of the devouring insect, which, if removed from the lode which it was working, would no longer be able to recover it or to distinguish between the lawful and the unlawful morsels. The larva of the Scolia, consuming its Cetonia-grub, has taught us all that we want to know on this subject in my earlier volume. (Chapters 2to 5 of the present volume contain the whole of the matter referred to above.--Translator's Note.) The only acceptable larvae are those supplied with a heap of small insects, which are attacked without any special art, dismembered at random and eaten up quickly. Among these I have tested such as chance threw in my way: those of various Bembeces, all fed on Flies, those of the Palarus, whose bill of fare consists of a very large assortment of Hymenoptera; those of the Tarsal Tachytes, supplied with young Locusts; those of the Nest-building Odynerus, furnished with Chrysomela-grubs; those of the Sand Cerceris, endowed with a pinch of Weevils. A goodly variety, as you see, of consumers and consumed. Well, to all of these the seasoning with honey proved fatal. Whether poisoned or disgusted, they all died in a few days.
A strange result indeed! Honey, the nectar of the flowers, the sole diet of the Bee-tribe in both its forms and the sole resource of the Wasp in her a adult form, is to the larvae of the latter an object of insurmountable repugnance and probably a toxic dish. Even the transformation of the nymphosis surprises me less than this inversion of the appetite. What happens in the insect's stomach to make the adult seek passionately what the youngster refused lest it should die? This is not a question of organic debility unable to endure a too substantial, too hard, too highly spiced dish. The grub that gnaws the Cetonia-larva, that generous piece of butcher's meat; the glutton that crunches its batch of tough Locusts; the one that battens on nitrobenzine-flavoured game: they certainly own unfastidious gullets and accommodating stomachs. And these robust eaters allow themselves to die of hunger or digestive troubles because of a drop of syrup, the lightest food imaginable, suited to the weakness of extreme youth and a feast for the adult besides! What a gulf of obscurity in the stomach of a wretched grub!
