﻿REPORT 
  OF 
  TSETSE-FLY 
  INVESTIGATION 
  IN 
  NIGERIA. 
  387 
  

  

  there 
  is 
  less 
  opportunity, 
  in 
  that 
  there 
  is 
  less 
  time 
  for 
  them 
  to 
  feed, 
  but 
  the 
  dull 
  

   weather 
  did 
  not 
  begin 
  until 
  the 
  middle 
  of 
  June, 
  the 
  early 
  tornado 
  season 
  like 
  the 
  

   late 
  one 
  at 
  the 
  end 
  of 
  the 
  rains 
  being 
  mostly 
  very 
  sunny. 
  The 
  most 
  reasonable 
  

   explanation 
  of 
  this 
  falling 
  away 
  in 
  nourishment 
  in 
  the 
  rains 
  seems 
  to 
  be 
  that 
  food 
  

   is 
  more 
  difficult 
  to 
  find 
  by 
  tachinoides 
  with 
  its 
  low 
  flight 
  owing 
  to 
  the 
  high 
  under- 
  

   growth, 
  and 
  perhaps 
  to 
  some 
  extent 
  that 
  its 
  food 
  is 
  less 
  concentrated. 
  

  

  The 
  point 
  has 
  been 
  developed 
  at 
  some 
  length 
  because 
  this 
  starved 
  condition 
  of 
  

   the 
  flies 
  during 
  the 
  rains 
  corresponds 
  with 
  the 
  restraint 
  in 
  breeding 
  mentioned 
  above 
  

   (see 
  Diagram 
  I) 
  and 
  is 
  possibly 
  the 
  explanation 
  of 
  this. 
  Fiske 
  gives 
  an 
  instance 
  

   with 
  palpalpis 
  where 
  a 
  great 
  increase 
  of 
  the 
  fly 
  on 
  an 
  island 
  in 
  Victoria 
  Nyanza 
  led 
  

   to 
  a 
  relative 
  reduction 
  of 
  food 
  supply 
  and 
  a 
  consequent 
  reduction 
  in 
  breeding. 
  In 
  

   this 
  case 
  of 
  tachinoides, 
  however, 
  it 
  is 
  not 
  certain 
  that 
  this 
  reduction 
  in 
  nourishment 
  

   is 
  wholly 
  the 
  cause 
  of 
  the 
  restrained 
  breeding, 
  since 
  it 
  would 
  seem 
  economical 
  that 
  

   a 
  long-lived 
  insect 
  like 
  the 
  tsetse 
  in 
  a 
  country 
  where 
  there 
  is 
  a 
  prolonged 
  dry 
  season 
  

   should 
  not 
  breed 
  in 
  the 
  rains, 
  when 
  many 
  of 
  its 
  pupae 
  must 
  inevitably 
  perish 
  and 
  

   its 
  young 
  emerge 
  under 
  adverse 
  conditions. 
  

  

  (g) 
  Conclusions 
  on 
  Food 
  of 
  G. 
  tachinoides. 
  

  

  The 
  conclusions 
  drawn 
  are 
  : 
  — 
  

  

  1. 
  G. 
  tachinoides 
  prefers 
  a 
  mammalian 
  host, 
  and 
  its 
  greater 
  agility 
  gives 
  it 
  a 
  

  

  wider 
  range 
  of 
  potential 
  hosts 
  in 
  this 
  class 
  than 
  morsitans 
  has. 
  

  

  2. 
  It 
  is 
  not 
  particularly 
  associated 
  with 
  antelopes, 
  but 
  feeds 
  on 
  them 
  to 
  a 
  

  

  moderate 
  extent. 
  

  

  3. 
  It 
  draws 
  a 
  considerable 
  proportion 
  of 
  its 
  food 
  from 
  reptiles, 
  especially 
  where 
  

  

  wild 
  mammals 
  are 
  scarce. 
  

  

  4. 
  It 
  is 
  a 
  very 
  adaptable 
  fly 
  as 
  regards 
  its 
  food 
  and 
  can 
  thrive 
  in 
  densely 
  popu- 
  

  

  lated 
  districts 
  where 
  the 
  wild 
  fauna 
  is 
  reduced 
  to 
  as 
  small 
  proportions 
  

   as 
  it 
  conceivably 
  could 
  be 
  in 
  tropical 
  Africa. 
  

  

  5. 
  It 
  finds 
  its 
  food 
  more 
  readily 
  in 
  forest 
  with 
  areas 
  free 
  from 
  undergrowth 
  and 
  

  

  is 
  consequently 
  better 
  nourished 
  in 
  the 
  dry 
  season 
  than 
  in 
  the 
  rains. 
  

  

  3. 
  Glossina 
  morsitans. 
  

  

  Observations 
  made 
  on 
  this 
  fly 
  are 
  in 
  agreement 
  with 
  the 
  generally 
  accepted 
  views 
  

   as 
  regards 
  its 
  food. 
  It 
  was 
  never 
  met 
  with 
  in 
  the 
  absence 
  of 
  big 
  game, 
  though 
  in 
  

   some 
  cases, 
  notably 
  at 
  Shellim 
  (Azare 
  Division), 
  this 
  was 
  excessively 
  scanty. 
  How- 
  

   ever, 
  the 
  presence 
  of 
  any 
  large 
  antelope 
  indicates 
  a 
  considerable 
  number 
  of 
  small 
  

   antelopes 
  and 
  pigs, 
  since 
  the 
  large 
  mammals 
  are 
  driven 
  out 
  or 
  exterminated 
  before 
  

   the 
  latter 
  approach 
  extinction. 
  At 
  the 
  same 
  time 
  there 
  are 
  large 
  areas 
  of 
  bush 
  in 
  

   the 
  Northern 
  Provinces 
  which 
  form 
  good 
  game 
  country 
  where 
  morsitans 
  is 
  not 
  found, 
  

   though 
  the 
  bush 
  appears 
  suitable 
  for 
  it. 
  Wherever 
  it 
  was 
  encountered, 
  with 
  the 
  

   solitary 
  exception 
  of 
  Dau, 
  quoted 
  above 
  (p. 
  384), 
  it 
  was 
  in 
  a 
  well 
  adjusted 
  balance 
  

   with 
  its 
  food 
  supply, 
  since 
  the 
  percentage 
  of 
  females 
  in 
  the 
  catch 
  was 
  always 
  rather 
  

   low, 
  varying 
  from 
  3 
  • 
  5 
  to 
  28 
  per 
  cent, 
  for 
  catches 
  of 
  over 
  20 
  flies. 
  We 
  were 
  seriously 
  

   pestered 
  ourselves 
  in 
  only 
  three 
  out 
  of 
  the 
  47 
  localities 
  where 
  the 
  fly 
  was 
  met 
  with, 
  

   viz. 
  (1) 
  at 
  Dau 
  ; 
  (2) 
  at 
  Sherifuri 
  (Azare 
  Division) 
  in 
  thorn 
  forest, 
  the 
  grass 
  of 
  which 
  

   had 
  just 
  been 
  burnt 
  off 
  ; 
  (3) 
  in 
  spots 
  around 
  Mashiwashi, 
  which 
  is 
  on 
  the 
  eastern 
  

   edge 
  of 
  a 
  morsitans 
  area 
  in 
  which 
  the 
  fly 
  is 
  very 
  abundant. 
  This 
  species 
  does 
  not 
  

   have 
  much 
  opportunity 
  of 
  feeding 
  on 
  domestic 
  stock, 
  except 
  in 
  the 
  few 
  instances 
  

   where 
  cattle 
  roads 
  pass 
  near 
  its 
  haunts, 
  since 
  the 
  stock 
  owners 
  recognise 
  its 
  areas 
  

   as 
  unhealthy 
  to 
  their 
  animals, 
  though 
  they 
  do 
  not 
  associate 
  the 
  evil 
  with 
  the 
  fly. 
  

   In 
  consequence 
  of 
  this 
  the 
  56 
  per 
  cent, 
  of 
  small 
  type 
  mammalian 
  blood 
  (the 
  blood 
  

   of 
  pigs 
  being 
  included 
  among 
  the 
  large 
  type 
  bloods) 
  found 
  by 
  dissection 
  (see 
  Table 
  II) 
  

  

  