﻿INVESTIGATIONS 
  INTO 
  THE 
  BIONOMICS 
  OP 
  GLOSSINA 
  PALPALIS. 
  

  

  415 
  

  

  Table 
  XXIX. 
  

  

  Showing 
  Degree 
  of 
  Protection 
  against 
  Predatory 
  Destructors 
  provided 
  for 
  

  

  pupae 
  of 
  Glossina 
  palpalis 
  by 
  good 
  Breeding 
  Places. 
  

  

  

  

  Find 
  of 
  Empty 
  Shells. 
  

  

  

  Locality. 
  

  

  

  

  

  Wema 
  Island, 
  

  

  

  

  

  

  February 
  1914. 
  

  

  Fly 
  

  

  Destroyed 
  by 
  

  

  Total. 
  

  

  Percentage 
  

  

  

  emerged. 
  

  

  predators. 
  

  

  destroyed, 
  

  

  First 
  Beach 
  

  

  46 
  

  

  

  

  46 
  

  

  o-o 
  % 
  

  

  Second 
  ,, 
  

  

  46 
  

  

  5 
  

  

  51 
  

  

  9'8 
  % 
  

  

  Third 
  

  

  292 
  

  

  7 
  

  

  299 
  

  

  2-3 
  % 
  

  

  Fourth 
  , 
  

  

  318 
  

  

  9 
  

  

  327 
  

  

  2'8 
  % 
  

  

  Fifth 
  

  

  213 
  

  

  3 
  

  

  216 
  

  

  1-4 
  % 
  

  

  Sixth 
  

  

  521 
  

  

  11 
  

  

  532 
  

  

  2'1 
  % 
  

  

  Eighth 
  „ 
  

  

  117 
  

  

  5 
  

  

  122 
  

  

  4-1 
  % 
  

  

  Total 
  and 
  average 
  

  

  1553 
  

  

  40 
  

  

  . 
  1593 
  

  

  2-5 
  % 
  

  

  The 
  need 
  for 
  the 
  secure 
  protection 
  afforded 
  by 
  good 
  breeding 
  places 
  in 
  the 
  case 
  of 
  

   an 
  insect 
  like 
  Glossina 
  is 
  fairly 
  obvious. 
  The 
  adult 
  has 
  taken 
  it 
  upon 
  itself 
  to 
  feed 
  

   and 
  protect 
  the 
  larva, 
  but 
  the 
  puparia 
  are 
  exposed 
  to 
  all 
  the 
  innumerable 
  parasitic 
  

   and 
  predatory 
  destructors 
  of 
  Dipterous 
  puparia 
  in 
  general, 
  which 
  are 
  usually 
  common 
  

   throughout 
  the 
  world. 
  Owing 
  to 
  the 
  fostering 
  care 
  lavished 
  upon 
  the 
  larva, 
  

   very 
  few 
  young 
  are 
  produced 
  — 
  less 
  than 
  four 
  per 
  month 
  per 
  female 
  — 
  and 
  it 
  is 
  

   doubtful 
  if 
  the 
  average 
  longevity 
  exceeds 
  four 
  or 
  five 
  months. 
  About 
  the 
  

   maximum 
  possible 
  rate 
  of 
  increase, 
  therefore, 
  would 
  be 
  10-fold 
  per 
  generation, 
  

   as 
  compared 
  with 
  anywhere 
  from 
  several 
  hundred 
  to 
  several 
  thousand 
  fold 
  potential 
  

   increase 
  for 
  Diptera 
  generally. 
  The 
  species 
  cannot 
  withstand 
  heavy 
  mortality 
  

   in 
  its 
  pupal 
  stages 
  under 
  such 
  conditions. 
  Secure 
  protection 
  for 
  the 
  puparia 
  is 
  

   necessary, 
  and 
  the 
  presence 
  of 
  the 
  female 
  in 
  seeking 
  localities 
  for 
  deposition 
  of 
  her 
  

   larvae 
  where 
  parasites 
  and 
  predatory 
  destructors 
  rarely 
  penetrate 
  is 
  extremely 
  

   useful 
  to 
  the 
  species. 
  It 
  is 
  doubtful 
  if 
  any 
  better 
  protected 
  places 
  for 
  breeding 
  

   exist 
  (at 
  all 
  commonly) 
  than 
  those 
  actually 
  selected 
  most 
  freely, 
  in 
  dry, 
  clean 
  deposits 
  

   of 
  beach 
  sand 
  or 
  gravel. 
  Except 
  for 
  the 
  ants 
  which 
  wander 
  over 
  the 
  surface, 
  such 
  

   spots 
  are 
  positively 
  avoided 
  by 
  nearly 
  all 
  insects 
  except 
  Glossina, 
  and 
  therefore 
  by 
  

   the 
  predatory 
  and 
  parasitic 
  destructors 
  of 
  insects 
  in 
  general 
  ;* 
  and 
  no 
  parasitic 
  or 
  

  

  * 
  It 
  is 
  possibly 
  significant 
  that 
  the 
  most 
  favoured 
  breeding 
  places 
  of 
  the 
  tsetse 
  and 
  

   of 
  its 
  principal 
  host, 
  the 
  crocodile, 
  are 
  virtually 
  identical. 
  Much 
  the 
  largest 
  deposits 
  

   of 
  puparia 
  have 
  been 
  found 
  within 
  a 
  few 
  yards 
  of 
  crocodile 
  nests, 
  in 
  the 
  same 
  type 
  of 
  

   soil, 
  and 
  under 
  the 
  same 
  type 
  of 
  vegetation 
  that 
  serves 
  partially 
  to 
  shade 
  the 
  female 
  

   crocodile 
  as 
  she 
  " 
  broods 
  " 
  above 
  her 
  egg 
  deposit. 
  

  

  An 
  almost 
  equally 
  striking 
  correlation 
  between 
  breeding 
  places 
  of 
  tsetse 
  in 
  vegetable 
  

   debris 
  and 
  basking 
  spots 
  of 
  Varanus, 
  coupled 
  with 
  the 
  finding 
  of 
  large 
  deposits 
  of 
  

   puparia 
  in 
  the 
  sunning 
  spots 
  of 
  situtunga, 
  suggests 
  that 
  the 
  specific 
  or 
  characteristic 
  

   preferences 
  displayed 
  by 
  the 
  flies 
  for 
  these 
  hosts 
  originated 
  in 
  the 
  circumstance 
  that 
  

   flies 
  feeding 
  on 
  them 
  were 
  most 
  likely 
  to 
  propagate 
  (instead 
  of 
  the 
  converse 
  : 
  that 
  flies 
  

   propagating 
  on 
  sand 
  beaches 
  or 
  dry 
  vegetable 
  debris 
  would 
  therefore 
  be 
  most 
  likely 
  

   to 
  feed 
  on 
  animals 
  inhabiting 
  the 
  same 
  localities.) 
  

  

  It 
  is, 
  indeed, 
  most 
  probable 
  that 
  the 
  preference 
  for 
  certain 
  hosts 
  and 
  for 
  certain 
  types 
  

   of 
  breeding 
  grounds, 
  now 
  developed 
  into 
  specific 
  characteristics, 
  originated 
  coincidentally, 
  

   and 
  together 
  served 
  to 
  segregate 
  Glossina 
  palpalis 
  from 
  its 
  congeners. 
  

  

  