This is a reference to the Hindu god of love, Kama, who, like Cupid, has a magical bow with magical arrows. (Comma overload)
In the narrow context of the verse, it's an allusion, and in the broader context of Indian poetry, it's a tradition; armed with the bird's-eye-view, it becomes a flaw in the context of the poem.
1: Allusion
From Shiva Purana 2.3.17.23:
Kāma said:—
[...]
I have only five arrows that are soft and flowery. My bow is of three types. That too is flowery. The bowstring consists of bees.
These bees are "wild" in that they've been set free from the bow of Lord Kama. There isn't really any scriptural story where the bees escape, nor are they characterized as being in captives. I think this is just Naidu being (as she often is) flowery; the allusion is also useful because it sets up the verse's string/spring rhyme.
Bees, associated as they are with spring, are used across the world to evoke the idyllic vernal setting that Naidu's going for here, and their use in Indian literature is no different. For Naidu, who, as verbose explains, frequently tries to romanticize a picturesque India, these humming, buzzing bees are perfect fodder for those purposes.
2: Tradition
Yet there's a deeper story here, one that shows how Naidu is part of a long tradition of Indian writers describing bees as wild. Most depictions of Kama include these bees, including this 1820s gouache piece offered on Wikipedia:
This is a very common depiction, and it seems that it has informed an idea in India that the Platonic bee belongs on the bowstring of Kama; whenever a bee stops on a flower to suck on nectar or whatever, it's off-duty, so to speak, and not in its 'natural' habitat. These bees, in other words, are indeed 'wild.'
We see this in the fact that Indian poets very frequently characterize their bees as wild.
For one instance, the 7th-century epic poem Bhattikavya (originally in Sanskrit), includes:
The trancëd Râma, lingering there awhile,
Loved in the laughing flowers his Lady's smile;
And in the wild-bee's murmur, sweetly stole
Her voice of music o'er his raptured soul.
And Kalidasa's Meghaduta from the 3rd/4th-century has:
Beneath the delicate bending of her brows,
Shows her dark pupil flashing wild with glee
In her pure pearly eye-ball, and allows
Short glimpses of a sight as fair to see
As a white jasmine-bud where sits the black wild bee.
Like her predecessors', Naidu's bees are also frequently wild. In June Sunset, there is this:
Where’er the foot of the bright shower passes
Fragrant and fresh delights unfold;
The wild fawns feed on the scented grasses,
Wild bees on the cactus-gold.
In A Rajput Love Song, there is:
Haste, O wild-bee hours, to the gardens of the sunset!
Fly, wild-parrot day, to the orchards of the west!
In Vasant Panchami:
O quench your flame, ye crimson gulmohors.
That flaunt your dazzling bloom across my doors,
Furl your white bells, sweet champa buds that call
Wild bees to your ambrosial festival.
3: Inconsistency
More critically, however, I think that Naidu is wrong to dismiss the bees. She asks them,
What do you know in your blithe, brief season
Of dreams deferred and a heart grown old?
Those bees that she dismisses do know of the heart's affair: By associating the bees with the god of love, her exposition a few lines earlier said just that. In Indian literature, the bee is not only a witness to moments of love and intimacy, it also understands and embodies it. Valerie Ritter, in Kama's Flowers: Nature in Hindi Poetry and Criticism, 1885-1925, argues that the bee has become a 'character' of poetry, and that its various relationships and intimate bonds with flowers and plants have made it into a symbol for the "profound abstraction of connection". The allusion, then, viewed with this perspective, becomes rather flawed in the context of the poem.
That Naidu says the opposite, going against both her own words and the historical motif her œuvre often uses, is kind of sad. "Love's old and changeless secret" which, according to Naidu, the winds have glimpsed, have also been seen by the bees, from the bowstring upon which they perch.
