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| Record Summary | Two clusters of egg masses on a single Elder leaf, overhanging a large depression in the track |
| Found as | Ovum |
| Date | 14 October 2017 |
| OS grid ref | OSGR: SU01 |
| Lat/Lon | 50° 50’ N, 1° 50’ W |
| Vice County | Dorset, VC no: 9 |
| Country | England |
| Voucher | 14 Oct 2017[C] (Please quote this in any queries about this record) |
Notes:
The egg masses were directly above a large depression in the track. Presumably this occasionally filled with water and the eggs were laid in anticipation that the larvae would fall and develop in the pool.
Some egg masses contained whitish embryos with two brown eyes. They were evidently laid as a single line of eggs in a zig-zag folded gelatinous tube.
Other (?older) masses contained wriggling brown larvae in a shared space within the jelly, apparently ready to move out. Perhaps they were waiting for rain, but only a few moved out when the jelly was wetted, so there appears to be a mechanism leading to gradual release. This presumably gives a continuous stream of larvae which repopulates the temporary puddle after every shower. Those arriving in the puddle that persists all winter will be the ones that survive, and the survivors arriving earliest will have longest to develop.
12 March 18:
Over the last two or three weeks, several of the larvae have left their case and died, even after adding aeration. Possibly they now need to feed on living vegetation.
Case lengths: 16mm, 20mm. (12 March)
Gentle pressure working up from the tail of the case will cause the larva to leave the tube when it immediately loses interest in it and wanders off. The 20mm case yielded a larva 18mm when extended.
The following literature was used to identify this find:
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